Work And Time

A can do a piece of work in 12 days.B is 60%more efficient than A.The number of days,B would take to do the same piece of work is
A)7 1/2 (7.5)
B)6 1/4 (6.25)
C)8
D)6

 

sol>

Ans is A)
b can work in 1 day is=1/12 + 1/12*60%
=2/15

so b can do work in 15/2=7.5 days