AMC 8 1999 Problem 16
AMC8 1999 年第 16 题
百分比★★★☆☆
Tori's mathematics test had 75 problems: 10 arithmetic, 30 algebra, and 35 geometry problems. Although she answered 70% of the arithmetic, 40% of the algebra, and 60% of the geometry problems correctly, she did not pass the test because she got less than 60% of the problems right. How many more problems would she have needed to answer correctly to earn a 60% passing grade?
Tori 的数学考试有 75 道题：10 道算术，30 道代数，35 道几何。虽然她做对了 70% 的算术题、40% 的代数题和 60% 的几何题，但她没有通过考试，因为她做对的题目不到 60%。她还需要多做对多少道题才能达到 60% 的及格成绩？
- A.1
- B.5
- C.7
- D.9
- E.11
正确答案 · Correct Answer
B
解析 · Solution
Solution 1
First, calculate how many of each type of problem she got right:
Arithmetic:
Algebra:
Geometry:
Altogether, Tori answered 7 + 12 + 21 = 40 questions correct. To get a 60% on her test overall, she needed to get questions right.
Therefore, she needed to answer 45 - 40 = 5 more questions to pass, so the correct answer is 5
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