AMC8 2014

AMC8 2014 · Q7

AMC8 2014 · Q7. It mainly tests Linear equations, Ratios & proportions.

There are four more girls than boys in Ms. Raub's class of $28$ students. What is the ratio of number of girls to the number of boys in her class?

在 Raub 女士的班级中，女生比男生多 4 人，该班共有 28 名学生。班上女生与男生人数的比例是多少？

(A) 3 : 4 3 : 4

(B) 4 : 3 4 : 3

(D) 7 : 4 7 : 4

(E) 2 : 1 2 : 1

Answer

Correct choice: (B)

正确答案：（B）

Solution

Let $g$ being the number of girls in the class. The number of boys in the class is equal to $g-4$. Since the total number of students is equal to $28$, we get $g+g-4=28$. Solving this equation, we get $g=16$. There are $16-4=12$ boys in our class, and our answer is $16:12=\boxed{\textbf{(B)}~4:3}$.

设班上女生人数为 $g$。男生人数为 $g-4$。由于学生总数为 28，人们得到方程 $g + g - 4 = 28$。求解该方程得 $g = 16$。班上有 $16 - 4 = 12$ 名男生，比例为 $16:12=\boxed{\textbf{(B)}~4:3}$。

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