Multiple choice

Find the wrong term in sequence : 17, 18, 22, 31, 46, 72

  1. 17

  2. 18

  3. 31

  4. 46
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Differences: 18-17=1, 22-18=4, 31-22=9, 46-31=15, 72-46=26. The sequence of differences is 1^2, 2^2, 3^2, 4^2 (which should be 16), 5^2 (which should be 25). 31+16 = 47. 47+25 = 72. So 46 is the wrong term.

AI explanation

The differences between the consecutive terms are 1, 4, 9, 15, and 26, which deviates from a standard pattern. The intended pattern uses the sum of squares of natural numbers, where 17 + 1 squared equals 18, 18 + 2 squared equals 22, and 22 + 3 squared equals 31. Following this, 31 + 4 squared equals 47, so the term 46 is incorrect.

Keep practicing — related questions