Question

X can do a piece of work in 30 days. Y can do it in 20 days, and z can do it in 24 days. In how many days will they all do it together?

Answer 1

Method 1:
L.C.M of 30,20 and 24= 120
Therefore, 120 is the total unit of work.
Share of X in 120 unit= 120/30=4
Share of Y in 120 unit= 120/20=6
Share of Z in 120 unit= 120/24=5
Amount of work when done together by them= 4+6+5= 15
Total amount of work= 120 units
No. Of days required when done by all three = 120/15= 8 days