1, 4, 9, 16, 25, ? — Aptitude Question
1, 4, 9, 16, 25, ?: Find the next term: 1, 4, 9, 16, 25, ? Answer and worked solution on CodeKairo.
- Topic: Number & Letter Series
- Section: Logical Reasoning
- Difficulty: Easy
- Time target: 35 seconds
Question
Find the next term:
1, 4, 9, 16, 25, ?
Options
- 30
- 35
- 36
- 49
Show the answer and the worked solution
Correct answer: C. 36
Worked solution
- The terms are 1², 2², 3², 4², 5².
- The next is 6² = 36.
Answer: 36.
The idea
Check the small squares and cubes before anything else. Squares up to 400 and cubes up to 1,000 cover almost every series question.
Shortcut. The gaps 3, 5, 7, 9 are the odd numbers, so the next gap is 11 and 25 + 11 = 36 — the same as reading the blank as the sixth square, 6².
Common trap. 49 — miscounting positions and writing 7²; the five given terms run from 1² to 5², so the blank is the sixth square.