Mark M. answered • 4d

Retired college math professor. Extensive tutoring experience.

Let x = number of gallons of 90% solution

Then, 5 - x = number of gallons of 30% solution

0.90x + 0.30(5 - x) = 0.45(5)

0.90x + 1.5 - 0.30x = 2.25

0.60x = 0.75

x = 1.25 gal

Use 1.25 gal of 90% solution and 3.75 gal of 30% solution.

Sam Z.

4d