答案:B
解析:
Choice B is correct. The recipe calls for a 3:2 ratio of cups of flour to cups of sugar. Set up a proportion to determine how many cups of sugar, s, Francisco should use if he uses 4 cups of flour:
3/2=4/s
Solving this equation for s yields:
s=4/3*2=8/3=2(2/3) cups of flour
Francisco should use 2(2/3) cups of flour to maintain the same ratio of flour to sugar.