Which number will replace the question mark to continue the given number…
2016
Which number will replace the question mark to continue the given number series?
1, 3, 7, 15, 31, ?
- A.
65
- B.
47
- C.
55
- D.
63
Attempted by 36 students.
Show answer & explanation
Correct answer: D
Look at the differences between consecutive terms: 3 - 1 = 2, 7 - 3 = 4, 15 - 7 = 8, and 31 - 15 = 16. The differences are doubling, so the next difference is 32. Therefore, the missing term is 31 + 32 = 63.