Let total work to be done = L.C.M. (24,16) = 48 units X can do a piece of work in 24 days, => X's efficiency =
48
24
=2 units/day Let Y's 1 day work = y units/day Now, X worked for 16 days and Y worked for (16-4) = 12 days ⇒ 2(16)+y(12)=48 ⇒ 32+12y=48 ⇒ 12y=48−32=16 ⇒ y=