Question

if 4 men can reap 100 hectares in 20 days, then how many hectares can 30 men reap in 42 days?

Answer 1

Answer is 1500


if 4 men can reap 100 hectares in 20 days
$100 \div 4 = 25$

then 1 man can reap 25 hectares in 20 days

if 1 man can reap 25 hectares in 20 days
$25 \div 20 = 1.25$


then 1 man can reap 1.25 hectares in 1 day

Now...

30 men can reap 37.5 hectares in one day

$1.25 \times 30 = 37.5$

30 men can reap 1500 hectares in 40 days

$37.5 \times 40 = 1500$