Let a1, a2, a3, ......., a10 be in G.P. with ai > 0 for i = 1, 2, ......., 10 and * be the set of pairs (r, k), r, k ∈ N (the set of natural numbers) for which
Then the number of elements is *, is
(1) 2
(2) 10
(3) Infinitely many
(4) 4
The correct option is (3).
Explanation: