Among 5 numbers a, b, c, d and e the relationships are: a, b, c are in AP and b, c, d are in GP and c, d, e are in HP. Find b, c, d if a = 2 and e = 18.

Question

$(a)\;4,6,9\qquad(b)\;2,6,18\qquad(c)\;4,6,8\qquad(d)\;-2,-6,18$