Question

Which two geometric sequence in the following list have the same ratio?

a. 4.3, 17.2, 68.8, 275.2
b.5, 15, 45, 135, 405
c -5, -15,- 45, -135,- 405
d. -4.8, -16.8, -58.8, -205.8, -720.3
e. 6.8, 23.8, 83.3, 291.55, 1,020.425

Answer 1

The ratio of a geometric sequence:

`r=(a_2)/(a_1)`


`a. \\ r=(17.2)/(4.3)=4 \\ \\ b. \\ r=(15)/(5)=3 \\ \\ c. \\ r=(-15)/(-5)=3 \\ \\ d. \\ r=(-16.8)/(-4.8)=3.5 \\ \\ e. \\ r=(23.8)/(6.8)=3.5`

Sequences b. and c. and sequences d. and e. have the same ratio.