Question

Gunpowder contains $75$% nitre and $10$% sulphur. Find the amount of gunpowder which carries $9kg$ nitre. What amount of gunpowder would contain $2.5kg$ sulphur?

Answer 1

Let $x㎏$ be the amount of gunpowder carries $9㎏$ nitre.

Then, $75$ % of $x=9\Rightarrow x=\frac{9}{0.75}=12㎏$

Hence, $12㎏$ gunpowder carries $9㎏$ nitre.

Let $y㎏$ be the amount of gunpowder which contains $2.5㎏$ sulfur.

Then $10$ % of $y=2.5\Rightarrow y=\frac{2.5}{0.1}=25$

Hence, $25㎏$ of gunpowder contains $2.5㎏$ sulphur.