Algebra 2 Word Problem

Question

Bob wants to make 20 gallons of a 33% saline solution by mixing together a 21% saline solution and a 45% saline solution. How much of each solution must he use?

An answer and explanation would be extremely helpful .

Answer 1

20(33) = x(21) + y(45)

x + y = 20

x = 20 - y

Substitute:

20(33) = (20 - y)(21) + y(45)

660 = 420 - 21y + 45y

240 = 24y

y = 10

x = 10