JEE Advance - Mathematics (1988 - No. 19)
If the first and the $$(2n-1)$$st terms of an A.P., a G.P. and an H.P. are equal and their $$n$$-th terms are $$a,b$$ and $$c$$ respectively, then
$$a = b = c$$
$$a \ge b \ge c$$
$$a + c = b$$
$$ac - {b^2} = 0$$