Problema Solution

A solution of 62% alcohol is to be mixed with a solution of 31% alcohol to form 310 liters of a 43% solution. How many liters of the 62% solution must be used?

Answer provided by our tutors

let the quantity of 62% solution be x litres

then the quantity of 31% solution is (310-x) litres

according to the given condition

(62/100)x+(31/100)(310-x)=(43/100)(310)

0.62x+96.1-0.31x=133.3

ie    0.31x=37.2

x=120

quantity of 62% solution is 120 litres