5 DECEMBER 09 www.afterschoool.tk 1

Time & Work & Time & Distance in Quantitative Aptitude

by :

DR. T.K. JAIN

AFTERSCHO☺OL

centre for social entrepreneurship

sivakamu veterinary hospital road

bikaner 334001 rajasthan, india

www.afterschoool.tk

mobile : 91+9414430763

5 DECEMBER 09 www.afterschoool.tk 2

10 people working 8 hours a day complete a work in 24 days. How many persons will be

required to complete the work in 16 days working 10 hours a day?

= 10 * 8/10* 24/16

=12 persons

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10men+6boys=20days, 12m+4boys=18days, in what time

will 8m+8b do the work?

12m+4b=1/18

10m+6b=1/20

solving it we get: m=240, b=720

thus 8men + 8boys will do it in 22.5 days

5 DECEMBER 09 www.afterschoool.tk 4

3300 men have provision for 32 days if 850 gram per head. After 7

days X more persons came and now the provision will last for 8days less if given 825 gm per

head. What is X?Total = 3300*32*.85=89760

7 days=19635,left= 70125=

70125/(17*.825)=5000

X=1700 ans.

5 DECEMBER 09 www.afterschoool.tk 5

A can do in 12 and B in 15 days, if they work together, how many

days are required?

1/12+1/15 = 27/180

reverse it = 6.67 days.

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A+B can do a work in 10 days, A can do it in 15 days. In how many

days B alone can do the work?

1/10 – 1/15

= 5/150

=1/30 or 30 days are required by B

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A and B can do a job in X days. A alone take 8 days more than X and B can take 18 days more than X,

what is X?

Formula = sqrt (8 *18)

= 12 Answer

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A works twice as fast as B. If B can do it in 12 days, how many

days are required by A+B?

1/6 +1/12 = ¼

= 4 days

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A is thrice as good as B and can do a work in 60 days less than B. In how many days can they do it

together?

1/30 + 1/90 = 4/90

= 22.5 days.

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A can do it in 25 days, B in 20 days. They work together for 5 days. A leaves. How much time

more is required?

Work done by A = 5/25 = 1/5

B has to do 4/5 , 20*4/5 =16

B has worked for 5 days, so 11 more days are required.

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A moves @ 90 KM per hour from X to Y. Returns from Y to X @ 60 KM per hour. He agains goes to Y @ 30 KM per hour. What is

his average speed?

1/3(1/90+1/60+1/30)

=49

or assume distance between X and Y 180, total time = 2+3+6 = 540/11 = 49

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X travels from A to B and Y start from B to A. X travels at 75 km

per hour. They finish the remaining journey after cross over in 2.66 and 3 hours respectively.

What is the speed of Y? Ratio of speed = opposite ratio of sq. Root of

remaining time

75:X = sqrt(3): Sqrt(2.66)

X = (75 * 1.63) / 1.73) = 70 km

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Theif run 50 km from police. Speed of theif is 60 km, what

should be the minimum speed of police to catch them before next

120 KM?

=(50)/(X-60)=2

2X-120=50

X=170 or X = 85 Ans.

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