A photographer wants to mix 5 liters of a 9% acetic acid solution with a 13% solution to get a 10% solution. How many liters of 13% solution must be added?

Answer 1

.09(5) + .14x = .10(5+x) = 5 + .1x

.04x = 5-.45

x = .05/.04 = 5/4 Liter of 14% mixed with 5 liters of 9% yield a mixture of 6 1/4 Liters of 10%

5/4 = 1.25 Liters of 14%

14 is 4 from 10

9 is 1 from 10

You need 4/1 = 4 times as much 9% as 14%

5 = 4(1.25) = 5