Question

HELP

How many quarts of pure antifreeze must be added to 3 quarts of a 10% antifreeze solution to obtain a 60% antifreeze solution?
Round to nearest tenth if possible

Answer 1

3.75 quarts, rounded to 3.8 quarts

Explanation:

3 quarts of solution is 10% antifreeze, so 0.3 quarts are already antifreeze, and 2.7 quarts are not.

a(the antifreeze we already have)+x(what we're going to add)= 1.5*2.7

Let me explain. If we have 60% antifreeze, 40% is not. 60/40=1.5

Substitute a for 0.3

0.3+x=4.05 Subtract 0.3 from both sides

x=3.75