Question

The second term in a geometric sequence is 50 . The fourth term in the same sequence is 112.5 . What is the common ratio in this sequence ?

Answer 1

Geometric an = ar^(n - 1)

Second term =ar² ⁻ ¹ = ar = 50

Fourth term =ar⁴ ⁻ ¹ =  ar³ = 112.5

ar = 50 ..........(a)

ar³ = 112.5......(b)

Equation (b)/(a)

ar³ / ar = 112.5/50

r² = 2.25

r = √2.25

r = 1.5

Common ratio = 1.5