Time and Work Questions

P and Q can do a project in 60 and 30 days respectively. In how many days can they complete 90% of the project if they work together?

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?

Mehdi can complete a work in 25 hours. If he is joined by Jahnavi who is 50% more efficient, in what time will they together finish the work?

A can do as much work in 4 days as B can do in 5, and B can do as much work in 6 days as C in 7. In what time will C do a piece of work which A can do in a week ?

A does 50% of a work in 12 days. He then calls in B and they together finish the remaining work in 8 days. How long B alone would take to complete the whole work?

A can do 75% of a job in 9 days and B can do half of the job in 8 days. If they work on it together, then in how many days can they do half of the job?

18 men or 36 boys working 6 hours a day can plough a field in 24 days. In how many days will 24 men and 24 boys working 9 hours a day plough the same field ?

X can complete 5/7 part of a work in 10 days and Y can complete 3/4 part of the same work in 9 days. In how many days will both complete 13/21 part  of the total work?