From the given series, which is the Arithmetic Progression (AP)?
A. 7, 18, 29, 40, ...
B. 3, 13, 23, 33, ...
C. 3, -8, -3, 18, ...
D. 2, -2, -6, -10, ...
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A, B and D only
A series is an arithmetic progression when every term is obtained by adding the same number (the common difference) to the term before it.
A. 7, 18, 29, 40, ... Correct. Each term is 11 more than the one before: 18 − 7 = 29 − 18 = 40 − 29 = 11.
B. 3, 13, 23, 33, ... Correct. The common difference is 10 throughout.
C. 3, -8, -3, 18, ... Incorrect. The differences are −11, +5 and +21, not the same, so this is not an AP.
D. 2, -2, -6, -10, ... Correct. Each term is 4 less than the one before; the common difference is −4, and a negative common difference is allowed.