A student needs 12 liters of 15% antifreeze solution. HOw much 10% antifreeze and how much 25% antifreeze should be added to obtain the desired mixture?

Answer 1

x = Liters of 25% solution

y = Liters of 10% solution

x + y = 12

.25x + .1y = 12(.15)

.25x + .1y = 1.8

.25x + .25y = .25(12)

.25x + .25y = 3

-.25x + .1y = 1.8

.15y = 1.2

y = 8

x + 8 = 12

x = 4

4 liters of 25% solution

8 liters of 10% solution