Question

PLEASE GIVE STEP BY STEP EXPLANATION
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 ?

Answer 1

Answer:

Ravi alone can do work in 15 hrs.

In one hour Ravi would do = 1 / 15 of work

Raman can do work in 12 hrs.

In one hour they both can do work = 1 / 12

In 1 hour both can do =

$\frac{1}{15} + \frac{1}{12} \\ \frac{5 + 4}{60} \\ \frac{9}{60} \\ \frac{3}{20}$

In one hr. = 3 / 20

total work in = 20 / 3 hours.