Question 998782
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Let x be the volume of pure antifreeze (in liters) and y be the volume of 10% antifreeze mixture (in liters).

Then you have two equations to determine x and y.

First one is 

x + y = 8.

The second equation is 

x + 0.1y = 0.775*(x+y).

It equalize the volume of the pure antifreeze before and after the mixing.

To solve the system, express x from the first equation, x = 8-y, and substitute it into the second equation. You will get


(8-y) + 0.1y = 0.775*((8-y) + y).

Simplify and solve:

8 - 0.9y = 0.775*8,

0.9y = 8 - 0.775*8,

0.9 y = 1.8,

y = {{{1.8/0.9}}} = 2.


How many liters of pure antifreeze?  6 liters.

How many liters of 10% antifreeze?   2 liters.
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