Question

What volume of ethyl alcohol and water must be mixed together to prepare 250 ml of 60% by volume of alcohol in water

Answer 1

% by volume means a solution that contains a certain amount of volume(mL) in $100mL$ of solution.

60% by volume of alcohol solution means each $100mL$ of the solution will have $60mL$ of ethyl alcohol.

So, $250mL$ of solution will have $=\frac{60}{100}\times 250$

$=150mL$ ethyl alcohol

Hence in a $250mL$ solution of 60% by volume of alcohol and water, alcohol should be $150mL$ and water should be $100mL$.