AMC 8 2013 Problem 4
AMC8 2013 年第 4 题
方程与不等式★★☆☆☆
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?
8 个朋友在餐馆吃饭，并且商定均摊费用。因为 Judi 忘记带钱了，她的其他 7 个朋友帮她垫付了费用，因此 7 个人每人额外多付了 2.5 美元。那么餐费总共是多少美元？
- A.$120
- B.$128
- C.$140
- D.$144
- E.$160
正确答案 · Correct Answer
C
解析 · Solution
Solution 1
Since Judi's 7 friends had to pay 2.50 dollars extra each to cover the total amount that Judi should have paid, we multiply 2.50 times 7 = 17.50 dollars is the bill Judi would have paid if she had money. Hence, to calculate the total amount, we multiply 17.50 times 8 = 140 dollars to find the total the 8 friends paid.
Let be the total bill the 8 friends split up; each person was supposed to pay . Since Judi forgot her money, we have to add to get the amount of money each of the 7 friends have to pay. After multipling by 7, we have . This is equal to because both sides represent the total bill. Solving for : m=140. edits by
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