Question

Lakshya and Punam can complete a particular task in 12 hours while Punam and Vishal can do the same task in 20 hours and Lakshya and Vishal can complete the same work in 10 hours .In how many hours will all three of them finish the task working together?

Answer 1

Lakshya and Punam work in an hour = 1 / 12
Punam and Vishal work in an hour = 1 / 20
Lakshya and Vishal work in an hour = 1 / 10

All three work in an hour = 1/12 + 1/20 + 1/10

LCM = 60

5/60 + 4/60 + 6/60
15/60
60/15
4

ANS they will take 4 hours to complete the work