Question

What is the value of the fourth term in a geometric sequence for which a1=10 and r =0.5

Answer 1

Answer: 1.25

Step-by-step explanation:

The explicit formula for the sequence is $a_{n}=10(0.5)^{n-1}$

Substituting in n=4,

$a_{4}=10(0.5)^{4-1}=\boxed{1.25}$