The correct answer to this question is C,10 liters. This questions has to do with averages.In relation to mathematics, an average is defined as a calculated central value of a set of numbers. This average is based onthe two solutions of sulphuric acid (acid+ water) with concentration of 50% and 80% respectively. Here is the math equation: 0.62 = [.50xn1 + .80 x n2] /[n1 + n2]

n3=(n1 + n2) litres of 62 % acid sol. is mixed with 6 lit of water (pure water is used so concentration of it is 0% --it doesnt contain any sulphuric acid at this stage).

.50 = [.62 x n3 + 0 x 6] /[n3 + 6]

.5 n3 + 3 = .62 n3

–> .12 n3 = 3 –> n3 = 300/12 –> n3 = 25 lit.

–> n1 + n2 = 25

putting n1= (3/2).n2 from (i)

(3/2).n2 + n2 = 25

Then we arrive at the answer –> 5/2 . n2 = 25 –> n2 = 10 lit.