Which of the following forms an arithmetic progression?
A
1, 1, 2, 2, 3, 3, ...
B
0.3, 0.33, 0.333, ...
C
1/2, 1/4, 1/8, ...
D
√5, √20, √45, √80, ...
Correct Option:
D
Explanation
Simplify the terms: √5 = √5, √20 = 2√5, √45 = 3√5 and √80 = 4√5. Thus the sequence is √5, 2√5, 3√5, 4√5, ... and the common difference is √5. A constant difference is the defining property of an arithmetic progression.
