Question

Find the sum of the geometric sequence 3, 15, 75, 375, … when there are 9 terms and select the correct answer below.

Answer 1

Answer:

  c.  1,464,843

Step-by-step explanation:

The sum of n terms of a geometric sequence with first term a1 and common ratio r is given by ...

  sn = a1(r^n -1)/(r -1)

Filling in the values a1=3, r=5, n=9, we get ...

  s9 = 3(5^9 -1)/(5 -1) = 1,464,843