Question

What is a formula for the nth term of the given sequence?
20,50, 125...

Answer 1

a(n) = 20*2.5^(n - 1)

Explanation:

Note that 50 is 2.5 times 20, and that 125 is 2.5 times 50. Thus the common factor is 2.5. The formula for the nth term is

a(n) = a(1)*r^(n - 1) => a(n) = 20*2.5^(n - 1)