A solution is 90% glycerin. If there are 4 gallons of the solution, how much water, in gallons must be addded to make a 75% glycerin solution
Answers: A) 1.8 B) 1.4 C) 1.2 D) 1.0 E) 0.8

Rationale: in 4 gallons of the solution there are 0.9 ∗ 4 = 3.80 gallons of glycerin . we want to add ww gallons of water to 4 gallons of solution so that these 3.6 gallons of glycerin to be 75 % of new solution : 0.9 ∗ 4 = 0.75 ( 4 + w ) - - > w = 0.8 answer : e .
Answer: E