Question

How many men will be required to plough $100$ acres of land is $10$ days if $10$ men require $8$ days to plough $20$ acres of land?

• A. $30$
• B. $40$
• C. $50$
• D. $60$

Answer 1

Answer: (B)

$40$

Area	No. of men	No. of days
$100$	$x$	$10$
$20$	$10$	$8$

More men more area $\therefore$ direct variation
More men less no. of days $\therefore$ inverse variation
$100:20::x:10$
$8:10$
$100\times 8\times 10=x\times 20\times 10$
$\Rightarrow x=\frac{8000}{200}=40$