Question

八个朋友在餐馆吃饭，并同意平均分摊账单。因为朱迪忘带钱，她的七个朋友每人额外支付 $\$2.50$ 来替她支付她应付的部分。总账单是多少？

Eight friends ate at a restaurant and agreed to share the bill equally. Because Judi forgot her money, each of her seven friends paid an extra $\$2.50$ to cover her portion of the total bill. What was the total bill?

$\$120$

$\$128$

$\$140$

$\$144$

$\$160$

答案：C

知识点：钱币

难度评级：770

小提示：

七个朋友合起来支付了朱迪的那一份

The seven friends together paid Judi’s share.

大提示：

朱迪的那一份等于每个朋友额外支付金额的 $7$ 倍

Judi’s share is $7$ times the extra amount each friend paid.

视频讲解：

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文字解答：

朱迪应付的那一份由大家额外支付的钱完全覆盖，所以她应付的金额为 $7 \cdot \$2.50 = \$17.50\text{。}$

因为每个人原本应付相同金额，所以总账单为 $8 \cdot \$17.50 = \$140\text{。}$

所以正确答案是 C。

Since Judi’s portion was fully covered by everyone’s contributions, the portion of the bill she was responsible for was equal to $7 \cdot \$2.50 = \$17.50.$

As everyone paid the same amount, we can conclude that the total bill is $8 \cdot \$17.50 = \$140.$

Thus, C is the correct answer.

2013 AMC 8 第 4 题