Question 272631
How many quarts of pure antifreeze must be added to 6 quarts of a 10% solution to obtain a 20% antifreeze soltuion? (Round to the nearest tenth.)

Let the quantity of pure antifreeze added be x

pure(100%)--------------- 10%------------------------- 20 % mix

x-------------------------6-------------------------- x+6  quarts

1x+0.6x=0.2(x+6)

1.6x= 0.2x + 1.2

1.6x-0.2x= 1.2

1.4x= 1.2
x= 1.2/1.4

0.85  quarts