# TANCET 2008 Quant Question 4 : Work Time

## Question

A father can do a certain job in x hours. His son takes twice as long to do the job. Working together, they can do the job in 6 hours. How many hours does the father take to do the job?

- 9
- 18
- 12
- 20
- 16

**Correct Answer :** 9 hours. Choice (1)

#### Explanatory Answers

The father completes the job in x hours.

So, the son will take 2x hours to complete the same job.

In an hour, the father will complete

of the total job.

In an hour, the son will complete

of the total job.

So, if the father and son work together, in an hour they will complete

+

of the job.

i.e., in an hour they will complete

of the job.

The question states that they complete the entire task in 6 hours if they work together.

i.e., they complete

of the task in an hour.

Equating the two information, we get

=

Cross multiplying and solving for x we get 2x = 18 or x = 9.

The father takes 9 hours to complete the job.

Correct Answer (1)

Level of difficulty : Moderate

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