# A Geometric Sequence has 3rd term of 12 and 5th term of 48. What are the possible values for the common ratio?

##### 1 Answer

Sep 3, 2017

# +-2 #

#### Explanation:

Suppose the first term of the GP is

# {a, ar, ar^2, ar^3, ..., ar^(n-1) } #

We are given that:

# 3^(rd) " term" = 12 => ar^2=12 # ..... [A]

# 5^(th) " term" = 48 => ar^4=48 # ..... [B]

Eq [B]

#(ar^4)/(ar^2)=48/12 #

# :. r^2=4 #

# :. r=+-2 #