An empty fuel tank is filled with brand Z gasoline. When the tank is 3/4 empty, it is filled with brand X 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 X gasoline. At this time, what percent of the gasoline in the tank is brand Z?  Choose the correct option: A) 41% B) 42% C) 43% D) 43.75% 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>D</result>
An empty fuel tank is filled with brand Z gasoline. When the tank is 3/4 empty, it is filled with brand X 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 X gasoline. At this time, what percent of the gasoline in the tank is brand Z?