UPSC Civil Services 2016 Prelims General Studies Paper II

W can do 25% of a work in 30 days.
⇒W can do

1

4

of a work in 30 days
∴W can do the complete work in 120 days.
X can do

1

4

of the work in 10 days
∴X can do the complete work in 40 days.
Y can do 40% of the work in 40 days.
⇒Y can do 100% of the work in 100 days
∴Y can do the complete work in 100 days.
Z can do

1

3

of the work in 13 days.
∴Z can do the complete work in 39 days.
Hence, it is clear from above results that Z will complete the work first.