Mensa IQ Test Mensa IQ Sequence Completion

Question 1

What comes next in the sequence: 2, 6, 18, 54, ___?

Accepted Answer

162

Answer

Each number is multiplied by 3 to get the next: 2×3=6, 6×3=18, 18×3=54, 54×3=162. This is a geometric sequence with a common ratio of 3.

Question 2

Complete the sequence: 1, 1, 2, 3, 5, 8, 13, ___?

Accepted Answer

21

Answer

This is the Fibonacci sequence where each number is the sum of the two preceding numbers: 5+8=13, 8+13=21. The Fibonacci sequence appears frequently in nature and mathematics.

Question 3

What number completes the sequence: 3, 7, 15, 31, 63, ___?

Accepted Answer

127

Answer

Each term follows the pattern: multiply by 2 and add 1. 3×2+1=7, 7×2+1=15, 15×2+1=31, 31×2+1=63, 63×2+1=127. Alternatively, these are 2^n - 1 for n = 2, 3, 4, 5, 6, 7.

Question 4

Complete the sequence: 1, 4, 9, 16, 25, ___?

Accepted Answer

36

Answer

These are perfect squares: 1², 2², 3², 4², 5², so the next is 6² = 36. Recognizing square numbers is a fundamental pattern in IQ-type sequence problems.

Question 5

What comes next: 2, 3, 5, 7, 11, 13, ___?

Accepted Answer

17

Answer

This is the sequence of prime numbers — numbers divisible only by 1 and themselves. After 13, the next prime is 17. The number 15 (3×5) and 16 (2⁴) are composite.

Mensa Practice Test Practice Test

Mensa Practice Test Practice Test

Mensa IQ Test Mensa IQ Sequence Completion