Multiple choice

Find the wrong term in the following series. 728 1330 2196 3374 4912 6851

  1. 4912

  2. 2196

  3. 1330

  4. 728

  5. 6851

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Checking each term: 728 = 9³ - 1 = 729 - 1 ✓, 1330 = 11³ - 1 = 1331 - 1 ✓, 2196 = 13³ - 1 = 2197 - 1 ✓, 3374 = 15³ - 1 = 3375 - 1 ✓, 4912 = 17³ - 1 = 4913 - 1 ✓, 6851 = 19³ - 1 = 6859 - 1 ≠ 6851 ✗. The pattern is n³ - 1 where n = 9, 11, 13, 15, 17, 19 (consecutive odd numbers starting from 9). The term 6851 breaks this pattern as 19³ - 1 = 6859 - 1 = 6858, not 6851. Hence 6851 is the wrong term.