A, B and C can do a piece of work in 11 days, 20 days and 55 days respectively. If B works daily and is supported by A and C on alternate days beginning with A, then in how many days will the work be finished?

Question

Question

This question was previously asked in

SSC CGL 2022 Tier-I Official Paper (Held On : 06 Dec 2022 Shift 1)

Answer 1

Given:

A, B and C can do a piece of work in 11 days, 20 days and 55 days respectively.

Calculation:

Total work = LCM(11, 20 and 55) = 220

Efficiency of A = 220/11 = 20

Efficiency of B = 220/20 = 11

Efficiency of C = 220/55 = 4

1st day work = (20 + 11) = 31

2nd day work = (11 + 4) = 15

2 days work = 31 + 15 = 46

Total pairs of days required to work

⇒ 220/46

⇒ 4 + 36/46

So, 4 × 2 = 8 days and remaining work = 36

On next day 31 of 36 will be done and rest 5 will be done on 10th day

5/15 = 1/3

So total days = 9 + 1/3

∴ Total days required = 9 + 1/3 days.

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