[" 11.Three men,A,B and C can do a piece of work in "9" hours,"18" hours and "12" hours respective "],[" How long will they take if they work together? "]

A, B and C can do a piece of work in10 days, 12 days and 15 days respectively. How long will they take to finish it if they work together?

Ravi can do a piece of work in 15 hours while Raman can do it in 12 hours. How long will both take to do it, woking together?

A can finish a piece of work in 12 hours while B can finish it in 15 hours. How long will both take to finish it, working together?

Three taps A, B and C can fill an overhead tank in 6 hours, 8 hours and 12 hours respectively. How long would the three taps take to fill the empty tank, if all of them are opened together?

If 36 men can do a piece of working 25 hours in how many hours will 15 men do it?

A can do a piece of work in 7 days of 9 hours each and B can do it in 6 days of 7 hours each. How long will they take to do it,working a together 8(2)/(5) a day?