AMC10 2020 A

AMC10 2020 A · Q4

AMC10 2020 A · Q4. 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，其间她的汽车每加仑汽油行驶30英里。她每英里获薪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。汽油开支是$4 \cdot 2 = 8$美元。她获薪$120 \cdot 0.50 = 60$美元，扣除汽油开支后2小时赚$60 - 8 = 52$美元，即每小时$26$。

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