Multiple choice general knowledge math & puzzles

the series 1,4 is in

  1. A.P

  2. H.P

  3. G.P

  4. Cant be said

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

With only two terms given (1 and 4), we cannot uniquely determine the type of progression. They could be in AP (common difference 3), GP (common ratio 4), or HP (reciprocals 1 and 1/4 with common difference -3/4). At least three terms are required to definitively classify a progression.