Question

Ravi and Rishi can do a piece of work in 24 days , Rishi and Ronit in 30 days , Ronit and Ravi in 40 days. They all work together for 4 days and then, Ravi left, In how many days can Rishi and Ronit finish the remaining work?
STEP BY STEP EXPLANATION PLEASE​

Answer 1

Step-by-step explanation:

(Ravi and Rishi)’s 1 day’s work =1/24

(Rishi and Ronit)’s 1 day’s work = 1/30(Ronit and Ravi)’s 1 day’s work = 1/40

On adding, we get

2 (Ravi + Rishi + Ronit)’s 1 day’s work = (1/24 + 1/30 + 1/40) = 1/10

So,(Ravi + Rishi + Ronit)’s 1 day’s work = 1/20

So, they all together can finish the work in 20 days.

Ravi’s 1 day’s work = [(Ravi + Rishi + Ronit)’s 1 day’s work] - [(Rishi + Ronit)’s 1 day’s work] =

(1/20 -1/30 ) = 1/60

So, Ravi alone can finish the work in 60 days.

Similarly, Rishi’s 1 day work = (1/20 - 1/40) = 1/40

So, Rishi alone can finish the work in 40 days

And Ronit’s 1 day work = (1/20- 1/24) = 1/120

So, Rishi alone can finish the work in 120 days.