Number and Letter Series aptitude questions
Number and Letter Series questions are part of the Reasoning section of placement aptitude tests. Check alternating positions before searching for a single pattern. Below are 5 worked examples with the answer and the working; practise ten fresh ones or take a timed mock when you are ready.
Example 1. Find the next number in the series: 29, 40, 53, 68, ?
- A. 68
- B. 84
- C. 85 (answer)
- D. 87
The terms are squares plus 4: 5^2 + 4, 6^2 + 4 and so on, so the next is 9^2 + 4 = 85.
Example 2. Find the next number in the series: 9, 13, 17, 21, ?
- A. 25 (answer)
- B. 29
- C. 24
- D. 21
Each term rises by 4, so the next term is 21 + 4 = 25.
Example 3. Find the next number in the series: 4, 8, 16, 32, ?
- A. 64 (answer)
- B. 96
- C. 70
- D. 32
Each term is multiplied by 2, so the next term is 32 * 2 = 64.
Example 4. Find the next number in the series: 3, 9, 27, 81, ?
- A. 243 (answer)
- B. 324
- C. 81
- D. 162
Each term is multiplied by 3, so the next term is 81 * 3 = 243.
Example 5. Find the next number in the series: 9, 16, 23, 30, ?
- A. 36
- B. 37 (answer)
- C. 30
- D. 44
Each term rises by 7, so the next term is 30 + 7 = 37.
More Reasoning practice elsewhere: IndiaBIX, LearnTheta. See the 60-day aptitude plan.