Question

Ravi can do a piece of work in 15 hours while Raman can do it in 12 hours. How long will both take to do it, working together?

Answer 1

we know that,

Number of hours Ravi required to do piece of work = 15 hours

Number of hours Raman required to do piece of work = 12 hours

∴ We can calculate, work done by Ravi in 1 day = 1/15

Work done by Raman in 1 day = 1/12

Now, work done by both Ravi and Raman together in 1 hour= 1/15 + 1/12 = 9/60 = 3/20

∴ They can do work together in 20/3 hours = 6 2/3 hours = 6 hours 40 minutes