Multiple choice

In the following number series, one number is wrong.Find that wrong number. 15 , 28 , 45 , 64 , 85 , 112 , 141

  1. 28

  2. 64

  3. 116

  4. 85

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

The series is 15, 28, 45, 64, 85, 112, 141. Pattern: +13, +17, +19, +21, +27, +29. Differences: 28-15=13, 45-28=17, 64-45=19, 85-64=21, 112-85=27, 141-112=29. Pattern should be consecutive odd numbers: 13, 15, 17, 19, 21, 23, 25, 27, 29. We have 13, (missing 15), 17, 19, 21, (missing 23), 27, 29. So 85 (after 21 jump, should be 21+23=104, not 85) or 64 is wrong. Let's recalculate: 15+13=28, 28+17=45, 45+19=64, 64+21=85. If pattern was +13, +15, +17, +19, +21: 15+13=28, 28+15=43 (not 45), 43+17=60 (not 64), 60+19=79 (not 85), 79+21=100 (not 112). So 85 is wrong - the +21 should continue but 85 makes the pattern break before 112's +27. Answer: 85 is wrong.

Keep practicing — related questions