Q:

A radiator contains 10 quarts of fluid, 30% of which is antifreeze. How much fluid should be drained and replaced with pure antifreeze so that the new mixture is 40% antifreeze?

Accepted Solution

A:
Answer:1 3/7 quarts should be drained off and replaced with pure antifreeze.1 3/7 β‰ˆ 1.4286 Current amount of antifreeze in quarts is -30/ 100 Γ— 10 = 340% ---> 4 quartsLet the amount drained of and replaced with antifreeze be x-The amount left after draining off is 10 βˆ’ x.The amount of antifreeze Β is 30/ 100 (10βˆ’x).30/100(10-x)+x=4 3-3/10x+x=43+x(1-3/10)=4x=1*10/7=1 3/7 quartscheck;10- 1 3/7 = 8 4/7=(30/100*8 4/7)+1 3/7=(3/10 * 60/7) + 10/7=3*6/7 + 10/7=28/7 =44 liters of pure antifreeze is mixed into 10 quarts.