Direction In each series, look for the degree and direction of change between the numbers. In other words, do the numbers increase or decrease, and by how much-
51.

7 9 66 12 14 66 17
A. 19 66
 B. 66 19
C. 19 22
 D. 20 66
Answer and Explanation
Answer: A

Explanation: This is an alternating addition series with repetition, in which a random number, 66, is interpolated as every third number. The regular series adds 2, then 3, then 2, and so on, with 66 repeated after each "add 2" step.




52.

3 8 10 15 17 22 24
A. 26 28
 B. 29 34
C. 29 31
 D. 26 31
Answer and Explanation
Answer: C

Explanation: This is an alternating addition series that adds 5, then 2, then 5, and so on.




53.

4 7 26 10 13 20 16
A. 14 4
 B. 14 17
C. 18 14
 D. 19 13
Answer and Explanation
Answer: E

Explanation: Two patterns alternate here, with every third number following the alternate pattern. In the main series, beginning with 4, 3 is added to each number to arrive at the next. In the alternating series, beginning with 26, 6 is subtracted from each number to arrive at the next.




54.

32 29 26 23 20 17 14
A. 11 8
 B. 12 8
C. 11 7
 D. 32 29
Answer and Explanation
Answer: A

Explanation: In this simple subtraction series, the numbers decrease by 3.




55.

16 26 56 36 46 68 56
A. 80 66
 B. 64 82
C. 66 80
 D. 78 68
Answer and Explanation
Answer: C

Explanation: Here, every third number follows a different pattern from the main series. In the main series, beginning with 16, 10 is added to each number to arrive at the next. In the alternating series, beginning with 56, 12 is added to each number to arrive at the next.