Which of the following list of numbers is/are in Geometric Progression (GP)?
(A) 6, 18, 54, 162...
(B) 2, 6, 18, 25...
(C) 3, 9, 27, 81...
(D) 4, 12, 36, 108, ...
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (C) and (D) only
A list is a geometric progression when every term divided by the term before it gives the same ratio.
(A) 6, 18, 54, 162... Correct. Each term is 3 times the one before (18, 54 and 162 are 3 × 6, 3 × 18 and 3 × 54).
(B) 2, 6, 18, 25... Incorrect. The ratio is 3 up to 18, so the next term would have to be 54; 25 is not 3 × 18, so the ratio breaks at 25.
(C) 3, 9, 27, 81... Correct. Each term is 3 times the one before.
(D) 4, 12, 36, 108, ... Correct. Each term is 3 times the one before (12, 36 and 108 are 3 × 4, 3 × 12 and 3 × 36).