Time and Work Questions

Prabodh has done 1/2 of a job in 30 days, Sapan completes the rest of the job in 45 days. In how many days can they together do the job?

Parvesh is three times as efficient as Dinesh. Parvesh takes 20 days less than Dinesh to complete a book. If both of them work together, then in how many days the book will be completed?

A and B together can complete a task in 12 days. However, if A works alone, completes half the job and leaves and then B works alone and competes the rest of the work, it takes 25 days in all to complete the work. If B is more efficient than A, how many days would it have taken B to do the work by herself?

A does 60% of a work in 15 days. He then calls B, and they together finish the remaining work in 5 days. How long B alone would take to do the whole work?

A does 80% of a work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work?

A can do 75% of a job in 18 days and B can do 25% of the job in 12 days. If they work on it together, in how many days can they do 75% of the job?

If A, B and C together do a job in 4 days, A and C together do the job in 4.5 days and B and C together do the job in 12 days then in how many days can C alone do the job?

A, B and C can together do a job in 9 days. C alone can do the job in 36 days. In how many days can A and B do 50% of the job working together?