Question

How many gallons of a 90% antifreeze solution must be mixed with 100 gallons of 25% antifreeze to get a mixture that

is 80% antifreeze? Use the six-step method.
You need gallons.
(Round to the Question Viewer ber.)
answer

Answer 1

550 gallons

Explanation:

Let
`x` be the number of gallons for the 90% antifreeze solution and
`x+100` be the total number of gallons that will contain 80% antifreeze solution:

`\displaystyle (0.90x+0.25(100))/(x+100)=0.80\\\\0.90x+25=0.80x+80\\\\0.10x+25=80\\\\0.10x=55\\\\x=550`

Therefore, you would need 550 gallons of the 90% antifreeze solution.