Question

Four pipes can fill a tank in $70$ min. How long will it take to fill the tank by $7$ pipes?

• A. $20min$
• B. $35min$
• C. $40min$
• D. None of these

Answer 1

The correct option is C $40min$

By the principle of inverse proportion
$4\times 70=7\times x$
$\Rightarrow x=\frac{4\times 70}{7}=40min$