6, 9, 15, 21, 24, 28, 30, 32, 33, 34, 35, 36, 37, 38, 39
A. 28
B. 21
C. 24
D. 30
Answer:A
6, 9, 15, 21, 24, 28, 30, 32, 33, 34, 35, 36, 37, 38, 39
A. 28 B. 21 C. 24 D. 30
Explanation: Except for 28, each of the numbers is a multiple of three.