WORKAND TIME MANAGEMENT
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| WORK AND TIME MANAGEMENT |
Important information:- In this chapter, we will study techniques to solve problems based on work and its completion time as well as number of persons required to finish the given work in stipulated time. Suppose that you are a contractor and you got a contract to construct a flyover in a certain time. For this, you need to calculate the number of men required to finish the work according to their work efficiency.
Important Relations:-
1. Work and Person Directly proportional (more work, more men and conversely more men, more work).
2. Time and Person Inversely proportional (more men, less time and conversely more time, less men). 3. Work and Time Directly proportional (more work, more time and conversely more time, mo re work).
## Note While solving these types of problems, the work done is always supposed to be equal to 1
Rule Q
If ratio of numbers of men required to complete a work is m : n, then the ratio of time taken by them will be n : m.
Ex. 1 If 12 men can finish a work in 20 days, then find the number of days required to complete the same work by 15 men.
Sol. We know that, if ratio of numbers of men required to complete a work is m : n, then ratio of time taken by them will be n: m.
According to the question, Ratio of numbers of men = 12 : 15 = 4 : 5 Ratio of times taken =5:4 Let us suppose 15 men can finish a work in x days. Then, 20 : x = 5 : 4 x = 16
# Required number of days =16
## If 3 men and 4 boys can do a piece of work in 8 day, then 6 men and 8 boys can do the same work in ? ## A and B can do a piece of work in 18 days. B and C in 24 days, C and A in 36 days. Find the time in which A, B and C working together can finish the work. ## A and B can do a piece of work in 18 days. B and C in 24 days, C and A in 36 days. Find the time in which A, B and C working together can finish the work. ## 10 men can make a wall in 8 days. How many men required to complete the same work in half day ? 1. A can complete a piece of work in 18 days and B can complete the same work in half time taken by A. Then, working together, what part of the same work they can complete in a day? (a) 1/6 (b) 1/9 (c) 2/5 (d) 2/7 (e) 2/9 Answer :- (a) 1/6 2. A and B together can do a piece of work in 12 days, while B alone can finish it in 30 days. A alone can finish the work in ? (a) 15 days (b) 18 days (c) 20 days (d) 25 days (e) None of the above Answer :- (c) 20 days 3. Aarti can do a piece of work in 6 days. In how many days will she complete the three time of work of same type? (a) 18 days (b) 21 days (c) 3 days (d) 6 days (e) None of the above Answer :- (a) 18 days 4. A and B can do a piece of work in 6 and 12 days, respectively. They (both) will complete the work in how many days? (a) 9 days (b) 18 days (c) 6 days (d) 4 days (e) None of the above Answer :- (d) 4 days 5. A alone can complete a work in 12 days and B alone can complete the same work in 24 days. In how
many days can A and B together complete the same work? (a) 6 days (b) 4 days (c) 10 days (d) 8 days (e) None of the above Answer :- (d) 8 days 6. X can complete a job in 12 days. If X and Y work together, they can complete the job in 6%f days. Y
alone can complete the job in (a) 10 days (b) 12 days (c) 15 days (d) 18 days (e) None of the above Answer :- (c) 15 days 7. If 3 men and 4 boys can do a piece of work in 8 day, then 6 men and 8 boys can do the same work in ? (a) 2 days (b) 4 days (c) 6 days (d) 16 days (e) None of the above Answer :- (b) 4 days 8. A can do a piece of work in x days and B can do the same work 3x days. To finish the work together
they take 12 days. What is the value of x ? (a) 8 (b) 10 (c) 12 (d) 16 (e) None of the above Answer :- (d) 16 9. 20 men can cut 30 trees in 4 hour . If 4 men leave the job, how many trees will be cut in 12 hour? (a) 72 (b) 80 (c) 68 (d) 79 (e) None of the above Answer :- (a) 72 10. A can do a piece of work in 4 days and B can complete the same work in 12 days. What is the number
of days required to do the same work together? (a) 2 days (b) 3 days (c) 4 days (d) 5 days (e) None of the above Answer :- (b) 3 days 11. 12 men can do a piece of work in 24 days. How many days are needed to complete the work, if 8 men do this work? (a) 28 (b) 36 (c) 48 (d) 52 (e) None of the above Answer :- (b) 36 (a) 6.5hour (b) 7.5hour (c) 9hour (d) 4.5hour (e) None of the above Answer :- (b) 7.5hour 13. A and B can do a piece of work in 18 days. B and C in 24 days, C and A in 36 days. Find the time in
which A, B and C working together can finish the work. (a) 8 (b) 16 (c) 24 (d) 36 (e) None of the above Answer :- (b) 16 14. A and B can do a piece of work in 72 days. B and C can do it in 120 days. A and C can do it in 90 days.
In what time can A alone do it? (a) 80 days (b) 100 days (c) 120 days (d) 150 days (e) None of the above Answer :- (c) 120 days 15. A and B can do a piece of work in 10 h. B and C can do it in 15 h, while A and C take 12 h to complete
the work. B independently can complete the work in ? (a) 12 h (b) 16 h (c) 20 h (d) 24 h (e) None of the above Answer :- (d) 24 h 16. A can do a piece of work in 10 days and B in 20 days. They begin together but A leaves 2 days before
the completion of the work. The whole work will be done in
? (a) 8days (b) 9days (c) 7 days (d) 5days (e) 10days Answer :- (a) 8days 17. A and B together can complete a work in
3 days. They started together but after 2 days, B left the work. If the work is completed after 2 more days,
B alone could do the work in how many days? (a) 5 (b) 6 (c) 7 (d) 10 Answer :- (b) 6 19. A and B can complete a job in 24 days working together. A alone can complete it in 32 days. Both of
them worked together for 8 days and then A left. The number of days B will take to complete the remaining
job is ? (a) 16 (b) 32 (c) 64 (d) 128 Answer :- (c) 64 20. A contractor undertook to do a certain piece of work in 18 days. He employed certain number of men
but 12 of them being absent from the very 1st day, the rest could finish the work in 30 days. Find the number of men originally employed. (a) 40 (b) 15 (c) 45 (d) 30 (e) None of the above Answer :- (d) 30 21. P and Q can finish a work in 30 days. They worked at it for 10 days and then Q left. The remaining
work is done by P alone in 20 more days. How long will P take to finish the work alone? (a) 30 days (b) 20 days (c) 60 days (d) 50 days (e) None of the above Answer :- (a) 30 days 22. A and B can do a piece of work in 60 days and 75 days, respectively. Both begin together but after a
certain time A leaves off. In such case B finishes the remaining work in 30 days. After how many days did
A leave? (a) 25 days (b) 21 days (c) 20 days (d) 24 days Answer :- (c) 20 days 23. Ajay can do a piece of work in 25 days and Sanjay can finish it in 20 days. They work together for 5
days and then Ajay goes away. In how many days will Sanjay finish the remaining work? (a) 11 days (b) 12 days (c) 14 days (d) None of these Answer :- (a) 11 days 24. A and B can complete a work in 8 days, working together. B alone can do it in 12 days. After working
for 4 days, B left the work. How many days will A take to complete the remaining work? (a) 16 days (b) 18 days (c) 20 days (d) 22 days (e) 24 days Answer :- (a) 16 days 25. 10 men can make a wall in 8 days. How many men required to complete the same work in half day ? (a) 80 (b) 100 (c) 120 (d) 160 Answer :- (d) 160 26. 6 boys can complete a piece of work in 16 hour . In how many hours will 8 boys complete the same work? (a) 10 (b) 8 (c) 12 (d) 14 (e) None of the above Answer :- (c) 12 27. In a hostel, there are 120 students and food stock is for 45 days. If 30 new students join the hostel, in
how many days will the complete stock be exhausted? (a) 38 (b) 40 (c) 32 (d) 36 Answer :- (d) 36 28. If 5 boys take 7 hour to pack 35 toys, how many boys can pack 65 toys in 3 hour ? (a) 26/3 (b) 39/3 (c) 45/3 (d) 65 /3 (e) None of the above Answer :- (d) 65 /3 29. 20 women can complete a piece of work in 7 days. If 8 more women are put on the job. In how many
days will they complete the work? (a) 4.5 days (b) 5 days (c) 5.5 days (d) 4.5 days Answer :- (b) 5 days 30. 40 men can build a wall 200 m long in 12 days, working 8 hour a day. What will be the number of days
that 30 men will take to build a similar wall 300 m long, working 6 hour per day ? (a) 32 days (b) 18 days (c) 36 days (d) 9 days Answer :- (a) 32 days Table of Contain:-
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