Ruchi, Khushi and Teju can do a piece of work in 30, 40 and 60 days respectively. In how many days can Ruchi do the work, if she is assisted by both Khushi and Teju on every third day?

Question

Question

This question was previously asked in

SSC CGL 2022 Tier-I Official Paper (Held On : 03 Dec 2022 Shift 1)

Answer 1

Given:

Ruchi can do the work in 30 days

Khushi can do the work in 40 days

Teju can do the work in 60 days

Formula used:

Work done = Time taken × Efficiency

Calculation:

Let the total work be 120 units [As LCM of 30, 40, 60 is 120]

So, efficiency of Ruchi, Khushi, Teju = 4, 3, 2

Now,

In 3 days total work completed = 4 + 4 + 9

⇒ 17 units of the work

In 21 days total work completed = 17 × 7

⇒ 119 units

Now remaining 1 unit will complete Ruchi in 1/4 days

So, total time = 21 + 1/4

⇒ \(\frac{85}{4}\) days

∴ In \(\frac{85}{4}\) days the work will be completed.