Rakesh can do a certain job in 12 days. Vipin is 60% more efficient than Rakesh. How many days will Vipin alone take to do the same job ?

If 36 persons can finish 50% of work in 12 days In how many days 72 person can finish the complete work?

X, Y and Z complete a work in 6 days. X or Y alone can do the same work in 16 days. In how many days can Z alone finish the same work?

X, Y and Z together can do a piece of work in 16 (4/11) days. X and Y together can do the same work in 20 days. In how many days will Z alone finish the 60% of the work?

A can complete a work in 4 minutes. B in 5 minutes, C in 6 minutes and D in 10 minutes respectively. The average number of units of work completed by them per minute will be

P can build a wall in the same time in which Q and R together can do it. If P and Q together could do it in 30 days and R alone in 40 days, in what time could Q alone do it?

A can do $\frac{1}{4}$th part of work in 12 days, B can do 50% work in 20 days , and C can do $\frac{1}{3}$rd of the same work in 15 days. Who complete the work first?