Question

An ore contains $20\%$ zinc. How many $kg$ of ore will be required to get $45kg$ of zinc?

Answer 1

Let $xkg$ of ore is required to get $45kg$ of zinc

Ore contains $20\%$ zinc.

According to the question, we have

$\Rightarrow 20\%$ of $x=45$

$\Rightarrow \frac{20}{100}\times x=45$

$\Rightarrow x=225$

Hence, $225kg$ of ore required to obtain $45kg$ of zinc.