If a, b, c are in AP, b - a, c - b and a are in GP, then a: b : c is
1 : 2 : 3
1 : 3 : 5
2 : 3 : 4
1 : 2 : 4
A.
Given that, 2b = a + cand c - b2 = b - aa∴ b - a2 = b - aa ⇒ b = 2a⇒ c = 3a⇒ a : b : c = 1 : 2 : 3