1)A train covers a distance in 50 min ,if it runs at a
speed
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of 48kmph on an average.The speed at which the train
must run
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to reduce the time of journey to 40min will be.
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1. Solution::
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Time=50/60 hr=5/6hr
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Speed=48mph
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distance=S*T=48*5/6=40km
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time=40/60hr=2/3hr
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New speed = 40* 3/2 kmph= 60kmph
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2)Vikas can cover a distance in 1hr 24min by covering
2/3 of
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the distance at 4 kmph and the rest at 5kmph.the total
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distance is?
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2. Solution::
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Let total distance be S
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total time=1hr24min
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A to T :: speed=4kmph
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diistance=2/3S
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T to S :: speed=5km
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distance=1-2/3S=1/3S
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21/15 hr=2/3 S/4 + 1/3s /5
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84=14/3S*3
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S=84*3/14*3
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= 6km
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3)walking at ¾ of his usual speed ,a man is late by 2
½ hr.
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the usual time is.
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3. Solution::
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Usual speed = S
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Usual time = T
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Distance = D
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New Speed is ¾ S
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New time is 4/3 T
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4/3 T – T = 5/2
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T=15/2 = 7 ½
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4)A man covers a distance on scooter .had he moved
3kmph
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faster he would have taken 40 min less. If he had
moved
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2kmph slower he would have taken 40min more.the
distance is.
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4.Solution::
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Let distance = x m
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Usual rate = y kmph
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x/y – x/y+3 = 40/60 hr
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2y(y+3) = 9x ————–1
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x/y-2 – x/y = 40/60 hr y(y-2) = 3x —————–2
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divide 1 & 2 equations
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by solving we get x = 40
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5)Excluding stoppages,the speed of the bus is 54kmph
and
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including stoppages,it is 45kmph.for how many min does
the bus
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stop per hr.
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5.Solution::
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Due to stoppages,it covers 9km less.
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time taken to cover 9 km is [9/54 *60] min = 10min
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6)Two boys starting from the same place walk at a rate
of
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5kmph and 5.5kmph respectively.wht time will they take
to be
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8.5km apart, if they walk in the same direction
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6.Solution::
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The relative speed of the boys = 5.5kmph – 5kmph = 0.5
kmph
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Distance between them is 8.5 km
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Time= 8.5km / 0.5 kmph = 17 hrs
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7)2 trains starting at the same time from 2 stations
200km
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apart and going in opposite direction cross each other
ata
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distance of 110km from one of the stations.what is the
ratio of
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their speeds.
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7. Solution::
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In same time ,they cover 110km & 90 km
respectively
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so ratio of their speed =110:90 = 11:9
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8)Two trains start from A & B and travel towards
each other at
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speed of 50kmph and 60kmph resp. At the time of the
meeting the
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second train has traveled 120km more than the
first.the distance
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between them.
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8. Solution::
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Let the distance traveled by the first train be x km
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then distance covered by the second train is x + 120km
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x/50 = x+120 / 60
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x= 600
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so the distance between A & B is x + x + 120 =
1320 km
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9)A thief steals a ca r at 2.30pm and drives it at
60kmph.the
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theft is discovered at 3pm and the owner sets off in
another car
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at 75kmph when will he overtake the thief
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9. Solution::
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Let the thief is overtaken x hrs after 2.30pm
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distance covered by the thief in x hrs = distance
covered by
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the owner in x-1/2 hr
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60x = 75 ( x- ½)
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x= 5/2 hr
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thief is overtaken at 2.30 pm + 2 ½ hr = 5 pm
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10)In covering distance,the speed of A & B are in
the ratio
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of 3:4.A takes 30min more than B to reach the
destion.The time
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taken by A to reach the destinstion is.
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10. Solution::
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Ratio of speed = 3:4
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Ratio of time = 4:3
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let A takes 4x hrs,B takes 3x hrs
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then 4x-3x = 30/60 hr
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x = ½ hr
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Time taken by A to reach the destination is 4x = 4 * ½
= 2 hr
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Modal Paper For Aptitude
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1) The average ages of three persons is 27 years.
Their ages are in the proportion of 1:3:5.What is the
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age in years of the youngest one among them.
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Sol: Let the age of three persons be x, 3x and 5x
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-- > 9x/3 =
27 -- > x = 9
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2) The average of 11 numbers is 50. If the average of
first 6 numbers is 49 and that of last
6 is 52.Find
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the 6th number.
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Sol: The total sum of 11 results = 11 * 50 = 550
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The total sum of first 6 results = 6 * 49 = 294
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The total sum of last 6 results = 6 * 52 = 312
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Sixth result = 294 + 312 – 550 = 56
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3) Find L.C.M of 852 and 1491.
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852) 1491 (1
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852
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639) 852 (1
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639
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213) 639 (3
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639
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0
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H.C.F of 852 and 1491 is 213
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: . L.C.M = 852*1491/213 = 5964
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4) The smallest number which when divided by 20, 25,
35, 40 leaves the remainder 6 When divided by
|
14, 19, 23 and 34 respectively is the difference
between divisor and The corresponding remainder is 6.
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: . Required number = (L.C.M of 20, 25, 35, 40) – 6
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= 1400-6 = 1394
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5) The least multiple of 7 which leaves a remainder 4
when divided by 6,9,15 and 18 is
|
L.C.M of 6,9,15 and 18 is 90.
|
Let x be the least multiple of 7, which when divided
by 90 leaves the remainder 4.
|
Then x is of the form 90k + 4.
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Now, minimum value of k for which 90k + 4 is divisible
by 4.
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: . x = 4 * 90 + 4 = 364
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6) Sum of three even consecutive numbers is 48, and
then least number is
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1) 16
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2) 18
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3) 20
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4) 14
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Sol: 4) Let the numbers be 2n, 2n+2 and 2n+4
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2n + (2n+2) + (2n+4) = 48
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6n = 48-6 = 42, n = 7
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Hence the numbers are
-- > 14, 16 and 18
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The least number is 14.
|
7) It being given that v 15 = 3.88, the best
approximation to v5/3 is
|
1) 0.43
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2) 1.89
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3) 1.29
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4) 1.63
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__ ___ __ __ __
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Sol: 3) x =
v5/3 = v5*3/3*3 =
v15 /v 9 = v15/3
= 3.88/3 = 1.29
|
8) Of the
two-digit numbers (those from 11 to 95, both inclusive) how many have a
Second digit
|
greater than the first digit?
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1) 37
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2) 38
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3) 36
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4) 35
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Sol: 3) 12 to 19 -- > 8
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23 to 29 -- > 7
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34 to 39 -- > 6
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45 to 49 -- > 5
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56 to 59 -- > 4
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67 to 69 -- > 3
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78 to 79 -- > 2
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89 -- > 1
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9) The Value of v24 + 3v64 + 4v28 is
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Sol: 24*1/2 + 43*1/3 + 28*1/4
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-- > 4 + 4 + 4 -- > 12
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10) 3 ¼ - 4/5 of 5/6 / 4 1/3 / 1/5 – ( 3/10 + 21 1/5 )
is equal to
|
Sol: 13/4 –
4/5 * 5/6 / 13/3 / 1/5 – ( 3/10 + 106/5 )
(use BODMASRULE)
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-- > 13/4 – 4/6 / 13/3 / 1/5 – 215/10 -- > 31/12 / 13/3 * 5 – 215/10
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-- > 31/12 / 65/3 – 43/2 -- > 31/12 / 130 – 129/6 -- >
31/12/1/6 = 31/12 * 6/1
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-- > 31/2 = 15 1/2
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1) 13 sheeps and 9 pigs were bought for Rs. 1291.85.If
the average price of a sheep be Rs.
74. What
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is the average price of a pig.
|
Sol: Average price of a sheep = Rs. 74
|
: . Total price of 13 sheeps
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= (74*13) = Rs. 962
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But, total price of 13 sheeps and 9 pigs
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= Rs. 1291.85
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Total price of 9 pigs
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= Rs. (1291.85-962) = Rs. 329.85
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Hence, average price of a pig
|
= (329.85/9) =
Rs. 36.65
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12) A batsman in his 18th innings makes a score of 150
runs and there by increasing his Average by 6.
|
Find his average after 18th innings.
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Sol: Let the average for 17 innings is x runs
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Total runs in 17 innings = 17x
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Total runs in 18 innings = 17x + 150
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Average of 18 innings = 17x + 150/18
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: . 17x + 150/18 = x + 6 -- > x = 42
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Thus, average after 18 innings = 42
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13) . Find the H.C.F of 777 and 1147.
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777) 1147 (1
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777
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370) 777 (2
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740
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37) 370 (10
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370
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0
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: . H.C.F of 777 and 1147 is 37.
|
14) The L.C.M of two numbers is 2310 and their H.C.F
is 30. If one number is 210 the Other is
|
The other number
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= L.C.M * H.C.F/given number
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= 2310*30/210 = 330
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15) The average of 50 numbers is 38. If two numbers
namely 45 and 55 are discarded, The average of
|
remaining numbers is?
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Total of 50 numbers = 50 * 38 = 1900
|
Average of 48 numbers = 1900-(45+55) / 48
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= 1800 / 48 = 37.5
|
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16) Divide 50 in two parts so that the sum of
reciprocals is (1/12), the numbers are
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1) 20,30
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2) 24,36
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3) 28,22
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4) 36,14
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Sol: 1) Let the numbers be x and y then
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X+y = 50. ………(i)
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1/x + 1/y = 12
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1/x + 1/50-x = 1/12..From (i) y = 50 – x
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-- > 50-x+x/x(50-x) = 1/12
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-- > x2-50x+600 = 0
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-- > (x-30) (x-20) = 0
|
&am
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Aptitude Material
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1) Five years ago the average age of a family of 3
members was 27 years. A child has Been born, due
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to which the average age of the family is 25 years
today. What is the Present age of the child?
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Sol: Average age of the family of 3 members
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5 years ago = 27 years
|
Sum of the ages of the 3 members now
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= (27 + 5) * 3 = 96 years
|
Average age of the family of 4 members now
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= 25 years
|
Sum of the ages of the 4 numbers now
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= 25*4 = 100 years
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Age of child = 100 – 96 = 4 years
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2) In a class of 20 students in an examination in
Mathematics 2 students scored 100
Marks each, 3 get
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zero each and the average of the rest was 40. What is
the average Of the whole class?
|
Sol: Total marks obtained by a class of 20 students
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= 2 * 100 + 3 * 0 + 15 * 40
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= 200 + 600 = 800
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: Average marks of whole class = 800/20 = 40
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3). The greatest number, which can divide 432, 534 and
398 leaving the same remainder 7 in each, is
|
Required number is the H.C.F of
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(432-7), (534-7) and (398-7)
|
i.e., H.C.F. of 425, 527, 391
|
Required number = 17
|
4) The sum of two numbers is 216 and their H.C.F is
27. The numbers are
|
. Let the
numbers be 27a and 27b
|
Then 27a + 27b = 216
|
a+b = 8
|
Value of co-primes a and b are (1,7) (3,5)
|
: . Numbers are (27*1, 27*7) = (27,189)
|
5) The greatest number of 4 digits which is divisible
by each one of the number 12,18,21 and 28 is
|
Greatest number of 4 digits is 9999
|
L.C.M of 12, 18, 21, 28 = 252
|
On dividing 9999 by 252, the remainder is 171
|
: . Required number is (9999-171) = 9828
|
6) Four prime numbers are arranged in ascending order
according to their magnitude.Product of first
|
three is 385 and the product of last three is 1001.
The greatest number is.
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1) 11
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2) 13
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3) 17
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4) 19
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Sol: 2) 385) 1001(2
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770
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231) 385(1
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231 (1
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154)231(1
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154
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77) 154(2
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154
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0
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Hence the product of the middle terms = 77
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Greatest prime number = 1001 / 77 = 13.
|
7) If the square root of 55625 is 75, then
|
____
____ ______
|
v5625 + v56.25 + v0.5625 is equal to
|
1) 82.25
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2) 83.25
|
3) 80.25
|
4) 79.25
|
____
_____ ______
|
Sol: 2) v5625
= 75; v56.25 = 7.5; v. 5625 =
.75
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-- > 75+7.5+0.75 = 83.25
|
8) Which of
the following integers has most number of divisors?
|
1) 176
|
2) 182
|
3) 99
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4) 101
|
Sol: 2) 176 = 2,4,8,11,16,22,44,88
|
182 = 2,7,13,14,26,91
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99 = 3, 9, 11, 33
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101= 101
|
9) 10) A boy was asked to find the value of 3/8 of a
sum of money. Instead of multiplying The sum by
|
3/8 he divided it by 3/8 and then his answer exceeded
by Rs. 55. Find the Correct be x.
|
Sol: Let amount be x
|
8/3* - 3/8 * = 55
|
-- > 64x – 9x/24 = 55 -- > 55x/24 = 55
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-- > x = 24*55/55 = 24
|
: . 3/8 of x = 3/8 * 24 = Rs.9
|
10) A boy was asked to find the value of 7/12 of a sum
of money. Instead of multiplying The sum by
|
7/12 he divided it by 7/12 and thus his answer
exceeded the correct Answer By Rs.95. Find the correct
|
answer.
|
Sol: Let sum = Rs. K
|
: . 12/7 k – 7k/12 = 95
|
-- > 144k – 49k/84
= 95 -- > k = 84
|
:. 7/12 k --
> 7/12 * 84 = Rs. 49
|
11) In a boat 25 persons were sitting. Their average
weight increased one kilogram when One man
|
goes and a new man comes in. The weight of the new man
is 70kgs. Find the Weight of the man who is
|
going.
|
Sol: Weight increased per person is 1 kg.
|
Total increase in weight = 25 kgs
|
Weight of new man is 70 kgs,
|
(Which means his weight is 25 kgs heavier)
|
The weight of the old man was 70 – 25 = 45 kgs
|
13) What is the greatest possible length that can be
used to measure exactly the following Lengths 7m,
|
3m 85cm, 12m 95cm?
|
The length to be measured is
|
700cm, 385cm, 1295cm.
|
The required length in cm is the H.C.F of 700, 385,
and 1295, which is 35 cm.
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