Question

How many men must be engaged to do a piece of work in 16 days which 24 men can do in 40 days ?

Answer 1

The number of men doing a work and the number of days taken are in inverse proportion.
Let the number of men doing the work in $16$ days be $a$
Then, $24:a::$ inverse ratio of $40:16$

$24\times 16=a\times 40$

Applying the rule, product of extremes $=$ product of means

$24\times 40=a\times 16$

$a=\frac{24\times 40}{16}$

$a=60$

Hence, $60$ men can do the work in $16$ days.