Question

6 men can complete electric fiting in a building in 7 days.how many days will it take 21 men to do the job.

Answer 1

6 x 7 =21 x a
a=42/21
a=2 days

Answer 2

This question is of Direct and inverse proportions

The following question is specifically of inverse proportion because
as the number of men decrease , the time taken to finish the work increases .

Let's proceed to the method

Let x be the men required
y be the days taken

Men. 6 21

Days 7. y2

Therefore,

x1y1 = x2y2

$6 \times 7 = 21 \times y2$


$\frac{6 \times 7}{21} = y2$
y2 = 2


Thus,

2 days will be required by the men to finish work in 21 days