Question

4 people can dig a trench in 3 hours. How long would it take 9 people? Give your answer in minuets.

Answer 1

$\huge\bold\green{Solution}\blue{ :}$

4 people can dig the trench in 3 hours i.e. 180 minutes .

Let 9 people dig the trench in x minutes.

A/q, we have

______________________
| Number of people | 4 | 9 |
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| Time ( in minutes ) | 180 | x |
______________________

Clearly, more people will take less minutes to dig the trench.

So, it is a case of inverse variation.

•°• 4 × 180 = 9 × x

=> 4 × 180 = 9x

=> x = 4 × 180 / 9

=> x = 80

Hence, the required time is 80 minutes.