Which one of the following is not an Arithmetic progression?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 2, 4, 8, 16, ...
An arithmetic progression has the same difference between every two consecutive terms. The differences in each option:
Option (1) 1, 3, 5, 7, ... — differences 2, 2, 2: an AP.
Option (2) 2, 4, 8, 16, ... — differences 2, 4, 8, which keep changing, so this is not an AP; each term is twice the one before, which makes it a geometric progression.
Option (3) −5, −10, −15, −20, ... — differences −5, −5, −5: an AP.
Option (4) 12, 16, 20, 24, ... — differences 4, 4, 4: an AP.