Question

A 60 litre solution of alcohol and water contains 20 litres of alcohol. How much alcohol must be added to produce of resolution of 50 litre alcohol?

Answer 1

3 answers · Other - Science

Best Answer

Let us assume we add "a" litre of alcohol to make the mixture 50%

so new qty. of alcohol = (20 + a) litre

and new total quantity of mixture will be = (60 + a) litre

so New % of alcohol in the mixture would be = Qty. of Alcohol in the mixture / Tot. quantity

50% = (20 + a) / (60 + a) ; 50% is same as 50 / 100 or 0.5 or ½

0.50*(60 + a) = (20 + a)

½*60 + ½ (a) = 20 + a

30 + ½ (a) = 20 + a

30 - 20 = a - ½ (a)

10 = ½ (a)

=>a = 20 litre

so we have to add 20 litre of alcohol, , so that total alcohol would become = 40 litre

and total qty of mixture would be 60 + 20 = 80 litre, which means mixture will have 50% alcohol as 40 litre is 50% of 80 litre.