A works twice as fast as B. If both of them can together finish a piece of work in 12 hours, then B alone can do it in

A does 20% less work than B. If A can finish a piece of work in 7(1)/(2) hours, them B can finish it in

A is twice as good as B and together they finish a piece of work in 16 days. The number of days taken by A alone to finish the work is

A works twice as fast as B and B works twice as fast as C. All three working together can finish a task in 4 days with the help of D. If D alone can finish the same task in 16 days, then in how many days will A alone finish 75% of the same task ?