A and B  can do a piece of work in 20 days and 25 days respectively . Efficiency of C  is 25% more than the efficiency of B . find the tome taken by C to do the complete work .

20

Efficiency of C is 25% more than the efficiency of B i.e.

ratio of        B   :   C

                  4    :   5

as 4R = 4   so, 5r = 5

Efficiency × Days = Total work

time taken by C to complete the work = \(\frac{100}{5}\)  = 20 days