AMC8 2010

AMC8 2010 · Q15

AMC8 2010 · Q15. It mainly tests Percent, Arithmetic misc.

A jar contains five different colors of gum drops: 30% are blue, 20% are brown, 15% are red, 10% are yellow, and the other 30 gum drops are green. If half of the blue gum drops are replaced by brown gum drops, how many of the gum drops will be brown?

一个罐子里有五种不同颜色的软糖：30%是蓝色的，20%是棕色的，15%是红色的，10%是黄色的，其余30个软糖是绿色的。如果将一半的蓝色软糖替换为棕色软糖，那么有多少个软糖是棕色的？

(A) 35 35

(B) 36 36

(D) 48 48

(E) 64 64

Answer

Correct choice: (C)

正确答案：（C）

Solution

We do $100-30-20-15-10$ to find the percent of gumdrops that are green. We find that $25\%$ of the gumdrops are green. That means there are $120$ gumdrops. If we replace half of the blue gumdrops with brown gumdrops, then $15\%$ of the jar's gumdrops are brown. $\dfrac{35}{100} \cdot 120=42 \Rightarrow \boxed{\textbf{(C)}\ 42}$

通过$100-30-20-15-10$计算绿色软糖所占百分比，得25%。因此总共有120个软糖。将一半蓝色软糖替换为棕色后，棕色软糖占罐子中15%。$\dfrac{35}{100} \cdot 120=42 \Rightarrow \boxed{\textbf{(C)}\ 42}$

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