SAT Math Multiple Choice Practice Question 15: Answer and Explanation

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Question: 15

15. In a sequence of evenly spaced numbers, the first term is 7, and the 20th term is 159. The fourth term of the sequence would be

A. 32
B. 31
C. 30
D. 29
E. 28

Correct Answer: B

Explanation:

B. Although there are 18 terms between 7 and 159, the increment must be applied 19 times. Because 159 - 7 = 152, and 152 ÷ 19 = 8, each term must be 8 units greater than the one before it. So the sequence begins 7, 15, 23, 31 . . . (and you have your answer).

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