Select the number from among the given options that can replace the question mark (?) in the following series.
31, 35, 51, 87, 151, ?, 395
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 251.
Given series: 31, 35, 51, 87, 151, ?, 395
35 - 31 = 4 (22)
51 - 35 = 16 (42)
87 - 51 = 36 (62)
151 - 87 = 64 (82)
251 - 151 = 100 (102)
395 - 251 = 144 (122)