Question

Tom、Dorothy 和 Sammy 一起度假，并同意平均分摊费用。旅途中 Tom 支付了 $\$105$ ，Dorothy 支付了 $\$125$ ，Sammy 支付了 $\$175$ 。为了平均分摊，Tom 给 Sammy $t$ 美元，Dorothy 给 Sammy $d$ 美元。 $t-d$ 是多少？

Tom, Dorothy, and Sammy went on a vacation and agreed to split the costs evenly. During their trip Tom paid $\$105,$ Dorothy paid $\$125,$ and Sammy paid $\$175.$ In order to share costs equally, Tom gave Sammy $t$ dollars, and Dorothy gave Sammy $d$ dollars. What is $t-d?$

$15$

$20$

$25$

$30$

$35$

答案：B

知识点：平均数钱币

难度评级：900

小提示：

先求总费用和每个人应承担的份额。

First find the total trip cost and each person’s fair share

大提示：

Tom 和 Dorothy 各把低于应付份额的差额给 Sammy。

Tom and Dorothy each pay Sammy the amount they are short of a fair share

解答：

总费用为 $\$105+\$125+\$175=\$405$ ，所以每人应承担 $\$405\div3=\$135$ 。

Tom 少付 $\$30$ ，Dorothy 少付 $\$10$ ，因此 $t=30$ 且 $d=10$ 。

所以 $t-d=30-10=20$ 。

所以正确答案是 B。

The total cost was $\$105+\$125+\$175=\$405$ , so each person’s share was $\$405\div3=\$135$ .

Tom paid $\$30$ less than his share, and Dorothy paid $\$10$ less than her share, so $t=30$ and $d=10$ .

Therefore $t-d=30-10=20$ .

Thus, B is the correct answer.

2013 AMC 10A 第 5 题

答案：B

难度评级：900

小提示：

大提示：

解答：

其他年份的第 5 题