Answer:
Option B
Explanation:
Plan
(i) a,b,c are in G.P ,
then they can be taken as a, ar, ar2 where r,(r ≠ 0) is the common ratio
(ii) Arithmetic mean of x1,x2,............xn
= x1+x2+....+xnn
Let a,b,c are a,ar, ar2 , where rε N
Also, a+b+c3=b+2
⇒ a+ar+ar2= 3(ar)+6
⇒ ar2-2ar+a =6
⇒ (r-1)2 = 6a
∵ 6/a must be perfect square a ε N
∴ a can be 6 only.
⇒ r−1=±1⇒r=2
and ab+a−14a+1=36+6−147=4