Multiple choice

Find the wrong term in the following number series. $8 \; 18 \; 80 \; 420 \; 2420 \; 15270$

  1. 18

  2. 80

  3. 15270

  4. 2420

  5. 8
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The series follows a cube multiplication pattern: ×1+10, ×3+6, ×5+20, ×7-140, ×9-450. Starting with 8: 8×1+10=18, 18×3+6=60 (not 80), 60×5+20=320 (not 420). If 80 is wrong, the correct term after 18 should be 60. Continuing: 60×5+20=320, 320×7-140=2100 (not 2420). The pattern of multipliers 1,3,5,7,9 (odd numbers) suggests 80 should be 60.

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