Question 559646
a car radiator has a capacity of 16 quartz and is filled with a 25% antifreeze solution. how much must be drained off and replaced with pure antifreeze to obtain a 40% antifreeze solution?

Initial conc = 25%Final conc = 40%

100% antifreeze x qts 
Antifreeze to be removed =x

(16-x)*0.25+1*x = 0.4(16)

4-0.25x +x = 6.4 

0.75x = 2.4

x = 3.2 qts