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Number and letter series
14 MDCAT Logical reasoning questions with answers and explanations.
Printable worksheet with answer key
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Find the next number: 2, 4, 8, 16, ?
- 1 64
- 2 32
- 3 30
- 4 24
Show answer
Correct answer: 32
Each number is double the one before it, so the next is 16 x 2 = 32.
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Find the next number: 3, 6, 11, 18, 27, ?
- 1 38
- 2 36
- 3 40
- 4 45
Show answer
Correct answer: 38
The differences are 3, 5, 7 and 9, which go up by 2 each time. The next difference is 11, so 27 + 11 = 38.
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Find the next number: 1, 4, 9, 16, 25, ?
- 1 36
- 2 34
- 3 49
- 4 30
Show answer
Correct answer: 36
These are the squares of 1, 2, 3, 4 and 5, so the next is 6 squared, which is 36.
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Find the next number: 100, 93, 86, 79, ?
- 1 72
- 2 69
- 3 73
- 4 71
Show answer
Correct answer: 72
Each number is 7 less than the one before it, so the next is 79 - 7 = 72.
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Find the next number: 2, 3, 5, 7, 11, 13, ?
- 1 17
- 2 15
- 3 19
- 4 21
Show answer
Correct answer: 17
These are the prime numbers in order. The next prime after 13 is 17.
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Find the next letter: A, C, E, G, ?
- 1 K
- 2 I
- 3 H
- 4 J
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Correct answer: I
The letters skip one each time, so after G (skipping H) comes I.
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Find the next letter: Z, X, V, T, ?
- 1 R
- 2 S
- 3 Q
- 4 P
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Correct answer: R
The letters move back two places each time. After T (skipping S) comes R.
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Find the next number: 1, 1, 2, 3, 5, 8, ?
- 1 15
- 2 11
- 3 13
- 4 12
Show answer
Correct answer: 13
Each number is the sum of the two before it, so the next is 5 + 8 = 13.
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Find the next pair: AZ, BY, CX, DW, ?
- 1 EX
- 2 EV
- 3 FV
- 4 EU
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Correct answer: EV
The first letter moves forward one place and the second moves back one place each time, so the next pair is EV.
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Find the next number: 5, 10, 20, 40, ?
- 1 80
- 2 100
- 3 60
- 4 70
Show answer
Correct answer: 80
Each number is double the one before it, so the next is 80.
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What comes next in the series 3, 6, 12, 24, ...?
- 1 36
- 2 30
- 3 42
- 4 48
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What comes next in the series 2, 5, 10, 17, 26, ...?
- 1 35
- 2 36
- 3 37
- 4 38
Show answer
Correct answer: 37
The differences are 3, 5, 7, 9, so the next difference is 11 and the term is 37.
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What comes next in the series A, C, F, J, ...?
- 1 M
- 2 N
- 3 O
- 4 P
Show answer
Correct answer: O
The gaps between letters increase by one each time: 2, 3, 4, then 5, so J plus 5 is O.
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What comes next in the series 1, 1, 2, 3, 5, 8, ...?
- 1 13
- 2 12
- 3 11
- 4 14