Q1. If 300 men can do a piece of work in 16 days, how many men would do (1/5) of the work in 15 days? Q2. If 4 men or 7 boys do a work in 29 days, 12 men and 8 boys will do the same work in Q3. One pipe can fill a pool 1.25 times faster than a second pipe. When both pipes are opened, they fill the pool in five hours. How long would it take to fill the pool if only the slower pipe is used? ANS: the slower pipe takes 11.25 hours Q4. If 20 men can build a wall 112 metres long in 6 days, what length of a similar wall can be built by 25 men in 3 days? Q5. Twenty workers can finish a piece of work in 30 days. After how many days could 5 workers leave the job so that the work is completed in 35 days? Q6. A, B and C can do a work in 5 days, 10 days and 15 days respectively. They started together to do the work but after 2 days A and B left. C did the remaining work (in days) Q7. If 20 men working 7 hours a day can do a piece of work in 10 days, in how many days will 15 men working for 8 hours a day do the same piece of work? Q8. If 27 kg of corn would feed 42 horses for 21 days, in hour many days would 36 kg of it feed 21 horses? Q9. Shyam can do a job in 20 days, Ram in 30 days and Singhal in 60 days. If Shyam is helped by Ram and Singhal every 3rd day, how long will it take for them to complete the job? Q10. A twice as good as a workman as B; and together they finish a work in 16 days. In how many days can it be done by each separately? Q11. 30 men working 5h a day can do a work in 16 days. In how many days will 20 men working 6 h a day do the same work? Q12. A swimming pool can be filled by an inlet pipe in 10 hours and emptied by an outlet pipe in 12 hours. One day the pool is empty and the owner opens the inlet pipe to fill the pool. However, he forgets to close the outlet. With both pipes open, how long will it take to fill the pool? Q13. If 12 boys can earn Rs 240 in 5 days, how many boys can earn Rs 420 in 21 days? END |
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Q1. If 300 men can do a piece of work in 16 days, how many men would do (1/5) of the work in 15 days?
(a)56 (b)64 (c)60 (d)72
ANSWER:
work = 300 x 16
1/5th of work = 60 x 16
men required to complete it in 15 days = 60 x 16 / 15 = 64 (b)
Q11. 30 men working 5h a day can do a work in 16 days. In how many days will 20 men working 6 h a day do the same work?
Ans:
Work W = 30 x 5 x 16
Days required = ( 30 x 5 x 16)/(20 x 6) = 20
Q5. Twenty workers can finish a piece of work in 30 days. After how many days could 5 workers leave the job so that the work is completed in 35 days?
Sol.
let after x days,
600 = 20x + 15(35 - x)
x = 15 days
Q4. If 20 men can build a wall 112 metres long in 6 days, what length of a similar wall can be built by 25 men in 3 days?
Sol: The lenght of wall = 112 x 25 x 3/(20 x 6)= 70 metres.
n/a
Q8. If 27 kg of corn would feed 42 horses for 21 days, in hour many days would 36 kg of it feed 21 horses?
(a)28 days
(b)42 days
(c)56 days
(d)31-1/2 days
Sol: Number of days= 36 x 42 x 21 /(21 x 27)
=56 days
(c)56 days
n/a
Q12. A swimming pool can be filled by an inlet pipe in 10 hours and emptied by an outlet pipe in 12 hours. One day the pool is empty and the owner opens the inlet pipe to fill the pool. However, he forgets to close the outlet. With both pipes open, how long will it take to fill the pool?
The alone time of the inlet pipe = 1/10 hours ,while that of outlet pipe =1/ 12 hours
When both the pipes are open then let "a" be the time to fill up the pool.
So, a(1/10-1/12)=1
=> a= 60 hours.
n/a
Q3. One pipe can fill a pool 1.25 times faster than a second pipe. When both pipes are opened, they fill the pool in five hours. How long would it take to fill the pool if only the slower pipe is used?
Sol: Let the time taken by slower pipe to fill the pool= 1.25 a hours
So the alone time of slower pipe=1/1.25a
And the time taken by faster pipe= a
Alone time =1/a
A/q, 5(1/1.25a+1/a)=1
=> a= 9 hours
So slower pipe will take =9 x 1.25=11.25 hours
n/a
Q6. A, B and C can do a work in 5 days, 10 days and 15 days respectively. They started together to do the work but after 2 days A and B left. C did the remaining work (in days)
(a)1
(b)3
(c)5
(d)4
Sol: Let the time taken by C to do the remaining work= a days
1 daysA/q, 5(1/5 +1/10) +(5+a)/15=1
Solving, a=
n/a
Q7. If 20 men working 7 hours a day can do a piece of work in 10 days, in how many days will 15 men working for 8 hours a day do the same piece of work?
(a)15-5/21 days
(b)11-2/3 days
(c)6-9/16 days
(d) 4-1/5 days
Sol: Let number of days= d
20 x 7 x 10 = 15 x 8 x d
d=35/3= 11-2/3 days
Ans: (b)11-2/3 days
n/a
Q9. Shyam can do a job in 20 days, Ram in 30 days and Singhal in 60 days. If Shyam is helped by Ram and Singhal every 3rd day, how long will it take for them to complete the job?
(a)12 days
(b)16 days
(c)15 days
(d)10 days
Sol: 1 day work of shyam= 1/20
1 day work of ram=1/30
1 day work of Singhal =1/60
2 day work of shyam=2/20=1/10
1 day work of shyam,ram and singhal together=(1/20+1/30+1/60)=1/10
So, after every 3 days amount of work completed=1/5
So to complete the total work the days required=5 x 1/5 = 15 days
Ans: (c)15 days
n/a
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