Question

How many gallons of a 70% antifreeze solution must be mixed with 90 gallons of 20% antifreeze to get a mixture that is 60% antifreeze?

gallons
The number of gallons that must be mixed is
(Round to the nearest whole number.)

Answer 1

360

Explanation:

If x is gallons of 70% antifreeze solution, then:

0.70x + 0.20(90) = 0.60(x + 90)

0.70x + 18 = 0.60x + 54

0.10x = 36

x = 360