Question

A solution contains 15% alcohol How much pure alcohol should be added to make the percentage of alcohol 32%?

Answer 1

Let amount of alcohol to be added be x.

Amount of alcohol in the 400mL solution = (15/100)×400=60mL

Now,

Add x mL alcohol to the solution.

((60mL+x)/(400mL+x))×100=32

(60mL+x)/(400mL+x)=32/100=8/25

1500mL+25x=3200mL+8x

17x=1700mL

x=100mL

So, 100mL of alcohol should be added.