Question

A can do a piece of work in 4 days. B can do it in 5 days. with the assistance of C they complete the work in 2 days. Find in how many days can C alone do it?

Answer 1

Answer:

I don't know

Explanation:

............

Answer 2

The answer is 20 days

Work done by A = 4

Work done by B = 5

Work done by C =?

By using LCM method

LCM of 4,5 = 20

Suppose 20 unit is total work done

A and B separate do one days work is

20/4 = 5 unit

and

20/5 = 4 unit

sum = 5 + 4 = 9 unit together one days

in two days.

9 × 2 = 18 unit

remaining work = 20 - 18 = 2 unit

it can do C in 2 days

means 1 days = 1 unit

total work ÷ 1

20/1 = 20 days

Ans = 20 days of C