Q23. At a fruit stand yesterday, the price of each apple was $0.10 more than the price of each orange. What was the total revenue from the sale of oranges at the fruit stand yesterday? (1) The number of oranges sold at the fruit stand yesterday was 5 more than the number of apples. (2) The total revenue from the sale of apples at the fruit stand yesterday was $15.00
答案是(C), 我选(E)
P=苹果价钱, P'=橙子价钱, N=苹果个数, N'=橙子个数
(1)N'=N+5 因为还有其他的未知数, 所以不充分 (2)P*N=15 不充分
(1)+(2): P*N=15=(P'+0.1)(N'-5)=15 P'*N'-5P'+0.1N'-0.5=15但是P'和N'的值未知, 所以不充分. 请问错在哪里? |