Maths-

General

Easy

Question

# A and B can finish a work in 20 days. A alone can do 1/5th of the work in 12 days. In how many days can B alone do it?

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 days.

### Let’s say that the total work can be represented as W and let’s say the amount of work that A can do in one day is W_{A} and the amount of work that B can do in one day is W_{B}.

Step 1 of 3:

It is given that A alone can do 1/5th of the work in 12 days.

So, Work done by A in one day(W_{A}) = = …….(1)

Step 2 of 3:

It is given that A and B can finish a work in 20 days. So we can write

W_{A } 20 + W_{B} 20 = W

Using equation (1)

_{ }+ W_{B} =

W_{B} =

Step 3 of 3:

Now, the time taken by B complete amount of work = 1 day

So, time taken by B to complete W amount of work = = 30 days

Final Answer:

Hence, the time that will B to complete the whole work is 30 days.

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