Answer:
405
Step-by-step explanation:
This is a geometric sequence, so we need the common ratio and the first term
To find the common ratio, we take the second term and divide by the first term
15/5 =3
The common ratio is 3
We are multiplying by 3 each time
The first term is 5
The formula is
an = a1 * (r) ^ (n-1) where n is the term number
We want the 5th term
a5 = 5 * (3) ^ (5-1)
a5 = 5 *3^4
= 5 *81
= 405
