A chemical company makes two brands of antifreeze The first

A chemical company makes two brands of antifreeze. The first brand is 65% pure antifreeze, and the second brand is 90% pure antifreeze. In order to obtain 140 gallons of a mixture that contains 70% pure antifreeze, how many gallons of each brand of antifreeze must be used? Note that the ALEKS graphing calculator can be used to make computations easier. First brand: gallons Second brand: gallons

Solution

let first antifreeze be x gallons ,second antifreeze be y gallons

total mixture x+y =140 gallons

(65/100)x+(90/100)y =(70/100)*140

65x +90y =9800

65x +90(140-x) =9800

65x +12600 -90x =9800

90x -65x =12600-9800

25x =2800

x=2800/25

x=112

x+y =140

112+y =140

y =140-112

y =28

first brand 112 gallons

second brand 28 gallons