Multiple choice

In the following number series only one number is wrong. Find out the wrong number (15 \quad 22 \quad 31 \quad 42 \quad 56 \quad 70)

  1. 15

  2. 31

  3. 56

  4. 42

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The differences between terms are: 22-15=7, 31-22=9, 42-31=11. These odd numbers increase by 2 each time. The pattern should continue: 56-42=14, but the difference should be 13. So 56 should be 42+13=55. Then 70-55=15 confirms 70 is correct. 56 breaks the odd number difference pattern (should be 55).

Keep practicing — related questions