Time and Work Questions

Both X and Y together can complete a work in 12 days and Y alone can complete the same work in 30 days. In how many days will X alone complete the work?

A, B and C together can complete a work in 25 days. If the ratio of efficiency of A, B and C is 15 : 10 : 6 respectively, then in how many days C alone can complete the same work?

Manish is four times as efficient as Puneet. Manish takes 90 days less than Puneet to complete a book. If both of them work together, then in how many days the book will be completed?

Manish can complete a work in 21 days and Karan can complete the same work in 28 days. If both together work for 7 days, then what fraction of total work is left?

20 boys do one fourth of work in 25 days. How many more boys will be required to complete the remaining work in 50 days?

Sumit is 28% less efficient than Amit. If Amit can make a wall in 54 days, then Sumit can complete the same work in how many days?

Vijay can do a work in 8 hours. Vijay and Puneet together can do the same work in 6 hours. Puneet and Sachin together can do the same work in 4 hours. Sachin alone can complete the same work in how many hours?

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?