AMC10 2011 B

AMC10 2011 B · Q2

AMC10 2011 B · Q2. It mainly tests Averages (mean), Arithmetic misc.

Josanna’s test scores to date are 90, 80, 70, 60, and 85. Her goal is to raise her test average at least 3 points with her next test. What is the minimum test score she would need to accomplish this goal?

Josanna 目前的测试分数是 90、80、70、60 和 85。她的目标是用下一次测试将平均分至少提高 3 分。她需要的最低测试分数是多少？

(A) 80 80

(B) 82 82

(D) 90 90

(E) 95 95

Answer

Correct choice: (E)

正确答案：（E）

Solution

Answer (E): The sum of her first 5 test scores is 385, yielding an average of 77. To raise her average to 80, her 6th test score must be the difference between 6 · 80 = 480 and 385, which is 95.

答案 (E)：她前 5 次测试的分数总和是 385，平均分是 77。要将平均分提高到 80，她的第 6 次测试分数必须是 6 · 80 = 480 与 385 的差，即 95。

Topics