急求数学题一道--恳请NN们帮忙,非常感谢~

Candy hearts were marked down from 30% to 50% on Valentine's Day. The following day, candy hearts were marked down an additional 25%. What was the lowest  cost of a candy heart that originally sold for $28?

(A) $7   (B) $12.6   (C) $14   (D) $15.4   (E) $21                   答案(A)

不明白这个additional 25%是针对哪个而言的?

我按照答案凑结果,得出这样的解题思路: 28 * (1-50%) - 28 * 25% = 7,也就是说additional 25%是相对于原价28而言的,而marked down an additional 25%又是针对28 * (1-50%)而言的~

NN们可以给我讲讲这种类型题目的读题技巧吗?我怎么能判断出来哪个比例是相对哪个量来说的呢?一旦碰到这种绕的题目我就崩溃了

提前谢过NN们了~

如果将additional 25% 理解为: 28*(1-50%)*(1-25%), 没有可以选择的答案。好多时候都是这样的，如果理解有歧义时，只有一种理解的答案是在ABCDE中的。另外一种理解见不到。

嗯,这样比较容易解决问题.一算到不对劲儿,赶紧换思路就好.