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?

1. 9
2. 18
3. 12
4. 20
5. 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

---

CAT, XAT, TANCET Practice Questions and Answers : Listed Topicwise

Number Theory		Permutation Combination		Probability		Inequalities
Geometry		Mensuration		Trigonometry		Data sufficiency
Percentages		Profit Loss		Ratio Proportion		Mixtures Alligation
Speed Time Distance		Pipes Cisterns		Interest		Races
Average, Mean		AP, GP, HP		Set Theory		Clocks Calendars
Algebra		Function		English Grammar		General Awareness