Time and Work Questions

A can do a work in 16 days and B in 20 days. If they work on it together for 8 days, then what fraction of work is left?

Working 5 hours a day, Shivam can read a book in 24 days. How many hours a day should he work so as to finish the same work in 8 days?

A can make a cupboard in 10 days and B can do it in 50 days. Along with C, they did the job in 6.25 days only. Then in how many days C alone can do the job?

If 15 persons can do a job in 30 days, then 30 persons with twice the efficiency can do the same job in how many days?

Both A and B together can complete a work in 20 days and B alone can complete the same work in 36 days. In how many days will A alone complete the work?

B is thrice as efficient as A and C is 0.75 times as efficient as A. What is the ratio of number of days taken by A, B and C when they work individually?

A can do a work in 24 days and B in 40 days. If they work on it together for 10 days, then what fraction of work is left?

An hour-long test has 60 problems. If a student completes 30 problems in 25 minutes, then the required seconds he has taken on average for computing each of the remaining problems is