The second and sixth terms of a G.P are 7

and 243/18, what is their common ratio?
A. 2.48
B. 3.68
C. 4.98
D. 1.18

1 answer

Let's assume that the common ratio of the GP is "r".

The second term of the GP is given as 7, so we can write the second term as:
7 = a * r^(2-1)
7 = a * r

Similarly, the sixth term of the GP is given as 243/18, so we can write the sixth term as:
243/18 = a * r^(6-1)
243/18 = a * r^5

Dividing the equations, we get:
(243/18)/(7) = (a * r^5) / (a * r)
243/126 = r^4

Taking the fourth root on both sides, we get:
(r^4)^(1/4) = (243/126)^(1/4)
r = (243/126)^(1/4)
r ≈ 1.18

Therefore, the common ratio is approximately 1.18, so the answer is D. 1.18.