Question

How much pure alcohol should be added to 400ml of strength 15% to make it’s strength 32%?

Answer 1

400ml has 15% alcohol i.e 60ml . This means we have 340ml of water or the liquid with which alcohol is mixed
Let V be the volume of alcohol added to make the strength 32%
then V/(340+V) = 32/100. solving this we get V as 160ml
But we already have 60 ml of alchohol in the given solution
so we need to add 160 -60 = 100ml of alcohol