AMC 8 1997 Problem 13
AMC8 1997 年第 13 题
百分比★★★☆☆
Three bags of jelly beans contain 26, 28, and 30 beans. The ratios of yellow beans to all beans in each of these bags are 50% , 25% , and 20% , respectively. All three bags of candy are dumped into one bowl. Which of the following is closest to the ratio of yellow jelly beans to all beans in the bowl?
三袋果冻豆分别装有 26、28 和 30 颗。这三袋中黄色豆与全部豆的比例分别是 50%、25% 和 20%。将三袋糖果全部倒入一个大碗中。黄色果冻豆与碗中全部果冻豆的比例最接近以下哪项？
- A.31%
- B.32%
- C.33%
- D.35%
- E.95%
正确答案 · Correct Answer
A
解析 · Solution
Solution 1
In bag , there are 26 jellybeans, and 50% are yellow. That means there are 26×50% = 26×0.50 = 13 yellow jelly beans in this bag.
In bag , there are 28 jellybeans, and 25% are yellow. That means there are 28×25% = 28×0.25 = 7 yellow jelly beans in this bag.
In bag , there are 30 jellybeans, and 20% are yellow. That means there are 30×20% = 30×0.20 = 6 yellow jelly beans in this bag.
In all three bags, there are 13 + 7 + 6 = 26 yellow jelly beans in total, and 26 + 28 + 30 = 84 jelly beans of all types in total.
Thus, of all jellybeans are yellow. Thus, the correct answer is
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