Question:
The third term of G.P. is 4. The product of its first 5 terms is
(A) 43
(B) 44
(C) 45
(D) None of these
Solution:
(C) 45
Explanation:
Given the third term of G.P, T3 = 4
To find the product of first five terms
We know that,
Tn = a rn – 1
It is given that, T3 = 4
⇒ ar3 – 1 = 4
⇒ ar2 = 4 … (i)
Product of first 5 terms = a × ar × ar2 × ar3 × ar4
= a5r1+2+3+4
= a5r10
= (ar2)5
= (4)5 [from (i)]
Hence, the correct option is (C)