1, 2, 4, 8, 16, ? — Number & Letter Series Aptitude Question
1, 2, 4, 8, 16, ?: Find the next term: 1, 2, 4, 8, 16, ? Answer and worked solution on CodeKairo.
- Topic: Number & Letter Series
- Section: Logical Reasoning
- Difficulty: Easy
- Time target: 30 seconds
Question
Find the next term:
1, 2, 4, 8, 16, ?
Options
- 24
- 30
- 32
- 64
Show the answer and the worked solution
Correct answer: C. 32
Worked solution
- Each term is twice the previous.
- Next = 32.
Answer: 32.
The idea
A constant ratio makes a geometric series. Divide two consecutive terms to find it.
Shortcut. The terms are 2⁰ to 2⁴, so the blank is 2⁵ = 32; each term is also one more than the sum of all before it (1 + 1 + 2 + 4 + 8 = 16).
Common trap. 24 — adding the last gap, 8, again (16 + 8); the gaps double as well, so the next one is 16.