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-
36.

9 12 11 14 13 16 15
A. 14 13
 B. 18 21
C. 14 17
 D. 12 13
Answer and Explanation
Answer: E

Explanation: This is a simple alternating addition and subtraction series. First, 3 is added, then 1 is subtracted, then 3 is added, 1 subtracted, and so on.




37.

4 8 22 12 16 22 20 24
A. 28 32
 B. 28 22
C. 22 28
 D. 32 36
Answer and Explanation
Answer: C

Explanation: This is an alternating repetition series, with a random number, 22, interpolated as every third number into an otherwise simple addition series. In the addition series, 4 is added to each number to arrive at the next number.




38.

40 40 31 31 22 22 13
A. 13 4
 B. 13 5
C. 4 13
 D. 9 4
Answer and Explanation
Answer: A

Explanation: This is a subtraction series with repetition. Each number repeats itself and then decreases by 9.




39.

1 10 7 20 13 30 19
A. 26 40
 B. 29 36
C. 40 25
 D. 25 31
Answer and Explanation
Answer: C

Explanation: Here, every other number follows a different pattern. In the first series, 6 is added to each number to arrive at the next. In the second series, 10 is added to each number to arrive at the next.




40.

10 20 25 35 40 50 55
A. 70 65
 B. 60 70
C. 60 75
 D. 60 65
Answer and Explanation
Answer: E

Explanation: This is an alternating addition series, in which 10 is added, then 5, then 10, and so on.