Question

$3$ pipes are required to fill a tank in $1$ hour. How long it will take to fill a tank by $5$ pipes?

• A. $8$
• B. $12$
• C. $24$
• D. $36$

Answer 1

The correct option is D $36$

This question is based on Inverse proprtion

According to the given conditions,

No. of pipes Time taken

$3$ $1$ hours

$5$ $x$ hours

By inversion proportion,

$3\times 1=5\times x$

$\therefore x=\frac{3\times 1}{5}$

$\therefore x=0.6$ hours

$\therefore x=0.6$ hours$\times 60$ minutes $=36$ minutes

Answer is $36$ minutes