AMC8 2007

AMC8 2007 · Q1

AMC8 2007 · Q1. It mainly tests Linear equations, Averages (mean).

Theresa's parents have agreed to buy her tickets to see her favorite band if she spends an average of 10 hours per week helping around the house for 6 weeks. For the first 5 weeks she helps around the house for 8, 11, 7, 12 and 10 hours. How many hours must she work during the final week to earn the tickets?

Theresa的父母同意如果她在6周内每周平均帮助家里做10小时家务，就给她买去看她最喜欢的乐队的门票。前5周她帮助家里的时间分别是8、11、7、12和10小时。最后一周她必须工作多少小时才能拿到门票？

(A) 9 9

(B) 10 10

(D) 12 12

(E) 13 13

Answer

Correct choice: (D)

正确答案：（D）

Solution

(D) The first 5 weeks Theresa works a total of $8+11+7+12+10=48$ hours. She has promised to work $6\times 10=60$ hours. She must work $60-48=12$ hours during the final week.

（D）前5周 Theresa 一共工作了 $8+11+7+12+10=48$ 小时。她承诺要工作 $6\times 10=60$ 小时。因此她在最后一周必须工作 $60-48=12$ 小时。

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