Question

Two jars contain equal quantities of 40% alcohol. Anju changed the concentration of the first jar to 50% by adding extra quantity of pure alcohol. Sonali changed the concentration of the second jar to 50% by replacing a certain quantity of the solution with pure alcohol. By what percentage is the quantity of alcohol added by Anju more than that replaced by Sonali ?
(a) 15%
(b) 10%
(c) 20%
(d) 40%
(e) None of these

Answer 1

0% alcohol solution is mixed with 19% alcohol solution to give 26% alcohol solution.

w1/w2 = (A2 - Aavg)/(Aavg - A1) = (40 - 26)/(26 - 19) = 14/7 = 2/1

So 2 parts of 19% solution were mixed with 1 part of 40% solution. This means that 2/3rd of the 40% solution was replaced by 19% solution.

Answer (B)

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