UPSC 2013 CDS 2 Math Paper

It is given that Y is 60% more efficient than X.
Suppose Y can complete the work in n days.
∴ n+60% of n=16
⇒n+

6

10

n=16⇒

16n

10

=16
⇒n=10
So, Y can complete the work in 10 days.
Trick:
Here x efficiency = 100%,
y efficiency = 160%
100×16=160×Dy
⇒Dy=10days