美国高考ACT考试数学练习题分享2

>>ACT数学：美国高考ACT考试数学练习题分享2

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3. So far, a student has earned the following scores on four 100-point tests this grading period:65,73,81, and 82. What score must the student earn on the fifth and last 100-point test of the grading period to earn an average test grade of 80 for the 5 tests?

A. 75

B. 76

C. 78

D. 99

E. The student cannot earn an average of 80.

解析：The correct answer is D. To find what the student needs to score on the fifth 100-point test to average a score of 80, you need to find the point total for the student so far by adding 65,73, 81 and 82. That sum is 301. Averaging 80 points on 5 tests means the student must earn 400 points (80·5). The acore needed on the last test is the difference,400～301, or 99.

正确答案选D。该学生前四次共得301分;5次考试平均分为80，意味着5次考试总分需达到400分，那么该学生最后一次考试需要达到的分数为400与301的差，即99分。

4. A rectangular lot that measures 150 ft by 200 ft is completely fenced. What is the approximate length, in feet, of the fence?

F. 300

G. 350

H. 400

J. 700

K. 1,400

解析：The correct answer is J. To find the length of fence needed to fence a rectangular lot 150 ft by 200 ft, you need to find the perimeter. The formula for the perimeter of a rectangle is 2 times the sum of the length and width, or P = 2( l+ w). 2(150 +200) =2(350) =700.

正确答案选J。所需篱笆的长度即为这块长150英尺宽200英尺矩形土地的周长。根据矩形周长公式，可知：矩形周长=2(长+宽)，即2(150 +200) =2(350) =700英尺。

5. The expression a[b+(c-d)] is equivalent to:

A. ab + ac - ad

B. ab + ac + ad

C. ab + ac - d

D. ab + c + d

E. ab + c - d

解析：The correct answer is A. To find an equivalent expression, multiply a by b+c-d. This results in a(b) + a(c) + a(-d), or ab + ac - ad.

正确答案选A。根据乘法分配率展开括号可得ab + ac - ad。

以上就是关于美国高考ACT的数学练习题的示例解析，非常实用。想要提高自己的ACT考试成绩，请坚持每天做练习，回顾知识点。就像这样每天完成数学题，并进行总结，日积月累，成绩就会有明显地提高。还想了解更多，就来坦途网ACT考试频道吧。