Multiple choice

Find the wrong number in the following number series. 20, 10, 12, 24, 75, 325

  1. 20

  2. 24

  3. 12

  4. 10

  5. 325
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Pattern: 20÷2+0=10, 10×1+2=12, 12×2+0=24, 24×3+3=75, 75×4+25=325. The operations are: ÷2+0, ×1+2, ×2+0, ×3+3, ×4+25. The last step to 325 follows ×4+25. Alternatively: 20, 10, 12, 24, 75, 325. If we check: 20÷2=10, 10+2=12, 12×2=24, 24×3+3=75, 75×4+25=325. The number 325 is marked as wrong (E).

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