AMC12 2020 A

AMC12 2020 A · Q3

AMC12 2020 A · Q3. It mainly tests Rates (speed), Arithmetic misc.

A driver travels for 2 hours at 60 miles per hour, during which her car gets 30 miles per gallon of gasoline. She is paid $0.50 per mile, and her only expense is gasoline at $2.00 per gallon. What is her net rate of pay, in dollars per hour, after this expense?

一位司机以 60 英里/小时的速度行驶 2 小时，其间她的车耗油 30 英里/加仑汽油。她每英里工资 0.50 美元，唯一开支是每加仑 2.00 美元的汽油。扣除此开支后，她的净时薪是多少美元/小时？

(A) 20 20

(B) 22 22

(D) 25 25

(E) 26 26

Answer

Correct choice: (E)

正确答案：（E）

Solution

The driver travels $2 \cdot 60 = 120$ miles, which requires $120 \div 30 = 4$ gallons of gasoline. Her gasoline expense is $4 \cdot \$2 = \$8$. She is paid $120 \cdot \$0.50 = \$60$, so after her gasoline expense, she makes $\$60 - \$8 = \$52$ in 2 hours, which is $\$$26 per hour.

司机行驶 $2 \cdot 60 = 120$ 英里，需要 $120 \div 30 = 4$ 加仑汽油。汽油开支为 $4 \cdot \$2 = \$8$。她收入 $120 \cdot \$0.50 = \$60$，扣除汽油开支后赚 $\$60 - \$8 = \$52$，2 小时即 $\$26/小时。

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