1, 8, 27, 64, ? — Number & Letter Series Aptitude Question
1, 8, 27, 64, ?: Find the next term: 1, 8, 27, 64, ? 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, 8, 27, 64, ?
Options
- 81
- 100
- 125
- 144
Show the answer and the worked solution
Correct answer: C. 125
Worked solution
- The terms are 1³, 2³, 3³, 4³.
- Next = 5³ = 125.
Answer: 125.
The idea
Cubes grow much faster than squares. Once two terms match a cube, the rest almost always follow.
Shortcut. The next cube is 5³, and every power of 5 ends in 5 — 125 is the only option that does, so no multiplying is needed.
Common trap. 81 — reading 64 as 8² instead of 4³ and continuing with 9²; the earlier terms 8 and 27 are not squares, so the series is cubes.