Maths-

General

Easy

Question

# A, B and C working together can do a piece of work in 8 hours. A alone can do it in 20 hours and B alone can do it in 24 hours. In how many hours will C alone do the same work?

Hint:

**Hint:**

When two quantities of different units are compared and expressed as a ratio, it is known as Rate. For example, a car travels at a speed of 100 kilometres per hour, then it means in one hour it covers 100 kilometres.

## The correct answer is: 30 hours.

### Let’s say the total work is represented as w

Step 1 of 2:

It is given that A alone can do the full work in 20 hours and B alone can do the full work in 24 hours and Let’s say that C alone can do the full work in t hours

So, work done by A in 1 hour =

Work done by B in 1 hour =

Work done by C in 1 hour =

Step 2 of 2:

It is also given that A, B and C working together can do a piece of work in 8 hours. So we can write

Work done by A in 8 hours + Work done by B in 8 hours + Work done by C in 8 hours = w

8 + 8 + 8 = w

8w( + + ) = w

t = 30 hours

Final Answer:

Hence, C alone can do the same work in 30 hours.

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