Using a geometric sequence, it is found that:
a) The explicit formula is: .
b) The value of her collection 9 years after she started tracking is of $94,557,148.
<h3>What is a geometric sequence?</h3>
A geometric sequence is a sequence in which the result of the division of consecutive terms is always the same, called common ratio q.
The nth term of a geometric sequence is given by:
In which is the first term.
Item a:
Three years ago, her collection was worth $250,000, hence the first term is .
In two years, the collection was valued at $1,102,500, hence the common ratio is:
.
Hence, the explicit formula is:
Item b:
The value of her collection 9 years after she started tracking is of $94,557,148.
More can be learned about geometric sequences at brainly.com/question/11847927