Respuesta :
.2(18-x)+x=.39(18)
x=4.275 quarts should be drained and replaced with pure antifreeze.
x=4.275 quarts should be drained and replaced with pure antifreeze.
4.275 quarts must be drained and replaced with a pure antifreeze.
What is percentage?
"It is a ratio that can be expressed as a fraction of 100."
For given example,
Let 'x' be the number of quarts that must be drained and replaced with a 100% solution.
The capacity of a car radiator is 18 quarts.
It is full of a 20% antifreeze solution.
So, the amount of mixture drained is,
20 percent of (18 - x)
⇒ (18 - x) × (20/100) = 0.20(18 - x)
18 quarts of a 39% solution
The value of 39 percent of 18 is,
⇒ 18 × (39/100) = 18 × 0.39
Th amount of solution drained and replaced with a 100% solution to give 18 quarts of a 39% solution.
⇒ 0.20(18 - x) + x = 18 × 0.39
⇒ 3.6 - (0.20)x + x= 7.02
⇒ (-0.20+1)x = 7.02 - 3.6
⇒ 0.8x = 3.42
⇒ x = 4.275 quarts
Therefore, 4.275 quarts must be drained and replaced with a pure antifreeze.
Learn more about the percentage here:
https://brainly.com/question/22111589
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