X can do ¼ of a work in 10 days, Y can do 40% of work in 40 days and Z can do 1/3 of work in 13 days. Who will complete the work first?

Detailed Solution:

Whole work will be done by X in 10*4 = 40 days. Whole work will be done by Y in (40*100/40) = 100 days. Whole work will be done by Z in (13*3) = 39 days Therefore, Z will complete the work first.