at a certain store, each notepad costs x dollars and each marker costs y dollars, if 10 is enough to buy 5 notepads and 3 markers, is 10 enough to buy 4 notepads and 4 markers instead?
(1) each notepad costs less than 1
(2) 10 is enough to buy 11 notepads.
答案是E.但是我不知道为什么?
这里的enough to 是不是不能认为等于?
也就是说不能推出10=5x+3y? 10=11x |