certain volume of ml of 25% alcohol is added to 200ml of 10% alcohol solution to obtain final solution of 15%

Question

A certain volume of ml of 25% alcohol is added to 200ml of 10% alcohol solution to obtain a final solution of 15%. Find the amount of ml of 25% added (in ml) and therefore the total amount of 15% solution

 

Hi! I need to work out an algebraic equation for this question and then solve it. Thanks :)

Answer 1

(x ml)(25%) + (200 ml)(10%) = (200 ml + x ml) (15%)

25x + 2000 = 3000 + 15x

10x = 1000

x = 100 mls 

 

Thus, 100 mls of 25% added to 200 ml of 10% gives 300 mls of 15%