SAT数学练习题 含详细答案及解析(4)

下面是几道SAT数学练习题，每道题目后面都有答案和详细的解析，希望同学们在练习的时候先不看答案，看看自己的能做对几道题，然后再与答案对照，找出错题原因，针对自己的SAT数学复习进行查漏补缺。

1. Jo's collection contains US, Indian and British stamps. If the ratio of US to Indian stamps is 5 to 2 and the ratio of Indian to British stamps is 5 to 1, what is the ratio of US to British stamps?

A. 5 : 1

B. 10 : 5

C. 15 : 2

D. 20 : 2

E. 25 : 2

2. A 3 by 4 rectangle is inscribed in circle. What is the circumference of the circle?

A. 2.5π

B. 3π

C. 5π

D. 4π

E. 10π

3. Two sets of 4 consecutive positive integers have exactly one integer in common. The sum of the integers in the set with greater numbers is how much greater than the sum of the integers in the other set?

A. 4

B. 7

C. 8

D. 12

E. it cannot be determined from the information given.

1.Correct Answer: E

Explanation:

Indian stamps are common to both ratios. Multiply both ratios by factors such that the Indian stamps are represented by the same number. US : Indian = 5 : 2, and Indian : British = 5 : 1. Multiply the first by 5, and the second by 2.

Now US : Indian = 25 : 10, and Indian : British = 10 : 2 Hence the two ratios can be combined and US : British = 25 : 2

2.Correct Answer: C

Explanation:

Draw the diagram. The diagonal of the rectangle is the diameter of the circle. The diagonal is the hypotenuse of a 3,4,5 triangle, and is therefore, 5. Circumference = π.diameter = 5π

3.Correct Answer: D

Explanation:

If two sets of four consecutive integers have one integer in common, the total in the combined set is 7., and we can write the sets as n + (n + 1) + (n + 2) + (n + 3 ) and (n + 3) + (n + 4) + (n + 5) + (n + 6) Note that each term in the second set is 3 more than the equivalent term in the first set. Since there are four terms the total of the differences will be 4 x 3 = 12