Time and work Quantitative aptitude question

[Q] A can do a piece of work in 20 days. B is 25% more efficient than A. The number of days taken by B to do the same piece of work is?

(a) 14 days
(b) 15 days
(c) 16 days
(d) 13 days

Solution

Answer   (c)
Explanation
----
Work done by A in 1 day = 1/20

Work done by B in 1 day = (1/20) × (125/100) = 5/80 = 1/16

=> B can complete the work in 16 days