Question

Chandra 向一家网络服务提供商支付固定月费，另按连接时长支付费用。她十二月的账单是 $\$12.48$ ；一月因为连接时间是十二月的两倍，账单为 $\$17.54$ 。固定月费是多少？

Chandra pays an on-line service provider a fixed monthly fee plus an hourly charge for connect time. Her December bill was $\$12.48,$ but in January her bill was $\$17.54$ because she used twice as much connect time as in December. What is the fixed monthly fee?

$\$2.53$

$\$5.06$

$\$6.24$

$\$7.42$

$\$8.77$

答案：D

知识点：方程组一次方程

难度评级：1030

小提示：

一月多出来的费用完全来自多用了一份十二月的连接时间。

The extra charge in January comes entirely from one additional December’s worth of connect time

大提示：

差额 $\$17.54 - \$12.48$ 就是十二月的连接时长费用。

The difference $\$17.54 - \$12.48$ equals December’s connect-time cost

解答：

一月只有连接时间翻倍，所以账单增加的 $\$17.54 - \$12.48 = \$5.06$ 就是十二月的连接时长费用。

因此固定月费是 $\$12.48 - \$5.06 = \$7.42$ 。

所以正确答案是 D。

January doubled only the connect time, so the increase $\$17.54 - \$12.48 = \$5.06$ equals December’s connect-time cost.

The fixed monthly fee is therefore $\$12.48 - \$5.06 = \$7.42.$

Thus, the correct answer is D.

2000 AMC 10 第 4 题

答案：D

难度评级：1030

小提示：

大提示：

解答：

其他年份的第 4 题