Question

Find the 11th term of the geometric sequence 10,20,40

Answer 1

10,240

Explanation:

First, we find the constant ratio by dividing a number by the previous number.

r = 40/20 = 2

Now we apply the formula for term a_n of a geometric sequence.

a_n = a_1 * r^(n - 1)

a_11 = 10 * 2^(11 - 1)

a_11 = 10 * 2^10

a_11 = 10,240

Answer 2

10, 20, 40

scale factor = x2

10, 20, 40, 80, 160, 320, 640, 1280, 2560, 5120, 10240

answer = 10,240