X can do 20% of a work in day, Y can do 25% of the same work in days and X, Y and Z together can do 50% of the same work in a day. How many per cert of work can be done by Z in day?
Correct Answer: 5%
Explanation:
Work done by (x + y + z) in 1 day
= 50% = 1/2
Work done by x in 1 days = 20% = 1/5
Work done by y in 1 days = 25% = 1/4 ∴ Work done by z in 1 day
= (1/2) - (1/5) - (1/4)
= (10 - 4 - 5)/20
= 1/20 = 5%
