2008 AMC 8 第 15 题

先试着解答 2008 AMC 8 第 15 题,然后核对你的答案与精心整理的解答,解答来自 LIVE by Po-Shen Loh。你也可以参加完整限时模拟考试、查看全部 2008 AMC 8 解答,或核对答案。

所有题目均经美国数学协会(MAA)官方合法授权使用。

15.

特蕾莎前 88 场篮球比赛分别得了 77、44、33、66、88、33、11 和 55 分。第九场她得分少于 1010 分,并且九场比赛的场均得分是整数。类似地,第十场她得分少于 1010 分,并且 1010 场比赛的场均得分也是整数。她第九场和第十场得分的乘积是多少?
In Theresa’s first 88 basketball games, she scored 7,7, 4,4, 3,3, 6,6, 8,8, 3,3, 11 and 55 points. In her ninth game, she scored fewer than 1010 points and her points-per-game average for the nine games was an integer. Similarly in her tenth game, she scored fewer than 1010 points and her points-per-game average for the 1010 games was also an integer. What is the product of the number of points she scored in the ninth and tenth games?
 35\ 35
 40\ 40
 48\ 48
 56\ 56
 72\ 72
答案:B
知识点:平均数整除性
小提示:
先把特蕾莎前 88 场的得分相加
First add Theresa’s scores from the first 88 games.
大提示:
99 场总分必须是 99 的倍数,1010 场总分必须是 1010 的倍数
The 99-game total must be a multiple of 9,9, and the 1010-game total must be a multiple of 10.10.
解答:
她前 88 场的得分和为 3737。因为前 99 场的平均分是整数,所以前 99 场的总分是 99 的倍数。
由于第九场得分少于 1010,前 99 场的总分在 3737 到 4747 之间,并且是 99 的倍数,因此总分为 4545。所以第 99 场得分为 45−37=845-37=8。
特蕾莎前 99 场的总分是 4545。因为前 1010 场的平均分是整数,所以前 1010 场的总分是 1010 的倍数。
由于第十场得分少于 1010,前 1010 场的总分在 4545 到 5555 之间,并且是 1010 的倍数,因此总分为 5050。所以第 1010 场得分为 50−45=550-45=5。
因此乘积为 8⋅5=408\cdot 5=40。
所以正确答案是 B。
The sum of her first 88 scores is 37.37. Since the average of the first 99 scores is an integer, the sum of the first 99 scores is a multiple of 9.9.
Since the score is less than 10,10, the sum of the scores after 99 games is between 3737 and 47,47, and is a multiple of 9,9, making the sum 45.45. Thus, the score of the 99th game is 45−37=8.45-37=8.
The sum of Theresa’s first 99 scores is 45.45. Since the average of the first 1010 scores is an integer, the sum of the first 1010 scores is a multiple of 10.10.
Since the score is less than 10,10, the sum of the scores after 1010 games is between 4545 and 55,55, and is a multiple of 10,10, making the sum 50.50. Thus, the score of the 1010th game is 50−45=5.50-45=5.
Therefore, their product is 8⋅5=40.8\cdot 5=40.
Thus, the answer is B .
LIVE by Po-Shen Loh
LIVE项目

LIVE直播课程

Self-Paced录播课程

启明星Star计划

奖学金项目

关于我们

罗博深是谁?

邮件联系

订阅英文简报

加入我们

申请明星导师

For a more Thought Full world.

© 2026 Expii, Inc.