Question

Two motor mechanics, Raju and Siraj, working together can overhaul a scooter in 6 hours. Raju alone can do the job in 15 hours. In how many hours can Siraj alone do it?

Answer 1

we know that,

Number of hours Raju required to overhaul the scooter = 15 hours

Let us consider number of hours Sriraj to overhaul the scooter = X hours

Number of hours required by Raju and Sriraj together to do piece of work = 6 hours

∴ We can calculate, work done by Raju in 1 hour = 1/15

Work done by Sriraj in 1 hour = 1/x

Work done by both Raju and Sriraj in a hour = 1/6

Work done by both Raju and Sriraj in 1 hour= 1/15 + 1/x = x+15/15x

x+15/15x = 1/6

6x + 90 = 15x

9x = 90

x = 90/9

x = 10

∴ Sriraj can do the work in 10 hours.