An empty fuel tank is filled with brand Z gasoline. When the tank is 3/4 empty, it is filled with brand Y gasoline. When the tank is half empty again, it is filled with brand Z gasoline. When the tank is half empty again, it is filled with brand Y gasoline. At this time, what percent of the gasoline in the tank is brand Z?
Choose the most appropriate option
A) 40%  B) 41%  C) 43.75%  D) 42%  E) 44%
Work with fraction of brand Z in the tank.   1st step: brand Z is 1   2nd step: brand Z is 1/2   3rd step: brand Z is (3/4)*(1/2) + 1/2 = 7/8   4th step: brand Z is (1/2)*(7/8) = 7/16 = 43.75%   Answer (43.75%)
<result>C</result>
An empty fuel tank is filled with brand Z gasoline. When the tank is 3/4 empty, it is filled with brand Y gasoline. When the tank is half empty again, it is filled with brand Z gasoline. When the tank is half empty again, it is filled with brand Y gasoline. At this time, what percent of the gasoline in the tank is brand Z?