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# How much of the 80% solution has been used in the entire process? There are two solutions of sulphuric acid (acid+ water) with concentration of 50% and 80% respectively. They are mixed in a certain ratio to get a 62% sulphuric acid solutions. This solution is mixed with 6 litres of water to get back 50% solution.

A. 15 liters
B. 12 liters
C. 10 liters
D. None of these

This question is part of Averages Level 1
Asked by Wyatt Williams, Last updated: Jun 30, 2020

### Request 0Follow Share     Answer AnonymouslyAnswer Later Copy Link   #### John Smith

John Smith 10 liters 1  1 Replied on Aug 22, 2017   Reply #### E. Good

E. Good

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]

–> 0.62 n1 + 0.62 n2 = .5 n1 + .8 n2

–> .12 n1 = .18 n2 –> 2 n1 = 3 n2 –> n1/n2 = 3/2 ………(i)

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.    Search for Google images Select a recommended image
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