Number and letter series

Written by Bilal Siddiqui (Logical Reasoning)

MDCAT · Logical reasoning · 14 questions

Name: ____________________ Date: ____________

Find the next number: 2, 4, 8, 16, ?
- A 64
- B 32
- C 30
- D 24
Find the next number: 3, 6, 11, 18, 27, ?
- A 38
- B 36
- C 40
- D 45
Find the next number: 1, 4, 9, 16, 25, ?
- A 36
- B 34
- C 49
- D 30
Find the next number: 100, 93, 86, 79, ?
- A 72
- B 69
- C 73
- D 71
Find the next number: 2, 3, 5, 7, 11, 13, ?
- A 17
- B 15
- C 19
- D 21
Find the next letter: A, C, E, G, ?
- A K
- B I
- C H
- D J
Find the next letter: Z, X, V, T, ?
- A R
- B S
- C Q
- D P
Find the next number: 1, 1, 2, 3, 5, 8, ?
- A 15
- B 11
- C 13
- D 12
Find the next pair: AZ, BY, CX, DW, ?
- A EX
- B EV
- C FV
- D EU
Find the next number: 5, 10, 20, 40, ?
- A 80
- B 100
- C 60
- D 70
What comes next in the series 3, 6, 12, 24, ...?
- A 36
- B 30
- C 42
- D 48
What comes next in the series 2, 5, 10, 17, 26, ...?
- A 35
- B 36
- C 37
- D 38
What comes next in the series A, C, F, J, ...?
- A M
- B N
- C O
- D P
What comes next in the series 1, 1, 2, 3, 5, 8, ...?
- A 13
- B 12
- C 11
- D 14

Answer key

1. B, 2. A, 3. A, 4. A, 5. A, 6. B, 7. A, 8. C, 9. B, 10. A, 11. D, 12. C, 13. C, 14. A

Each number is double the one before it, so the next is 16 x 2 = 32.
The differences are 3, 5, 7 and 9, which go up by 2 each time. The next difference is 11, so 27 + 11 = 38.
These are the squares of 1, 2, 3, 4 and 5, so the next is 6 squared, which is 36.
Each number is 7 less than the one before it, so the next is 79 - 7 = 72.
These are the prime numbers in order. The next prime after 13 is 17.
The letters skip one each time, so after G (skipping H) comes I.
The letters move back two places each time. After T (skipping S) comes R.
Each number is the sum of the two before it, so the next is 5 + 8 = 13.
The first letter moves forward one place and the second moves back one place each time, so the next pair is EV.
Each number is double the one before it, so the next is 80.
Each term is double the previous term.
The differences are 3, 5, 7, 9, so the next difference is 11 and the term is 37.
The gaps between letters increase by one each time: 2, 3, 4, then 5, so J plus 5 is O.
Each term is the sum of the two before it.