2, 3, 5, 7, 11, ? — Number & Letter Series Aptitude Question
2, 3, 5, 7, 11, ?: Find the next term: 2, 3, 5, 7, 11, ? Answer and worked solution on CodeKairo.
- Topic: Number & Letter Series
- Section: Logical Reasoning
- Difficulty: Easy
- Time target: 35 seconds
Question
Find the next term:
2, 3, 5, 7, 11, ?
Options
- 12
- 13
- 14
- 15
Show the answer and the worked solution
Correct answer: B. 13
Worked solution
- The terms are the primes 2, 3, 5, 7, 11.
- The next prime is 13.
Answer: 13.
The idea
If no arithmetic rule fits, check for primes, squares or cubes. Irregular gaps that never repeat usually mean primes.
Shortcut. Only one option is prime: 12 and 14 are even and 15 = 3 × 5, which leaves 13.
Common trap. 15 — adding the last gap, 4, again (11 + 4); prime gaps follow no rule, and 15 = 3 × 5 is not prime.