Josiah invests [tex]\$360[/tex] into an account that accrues [tex]3\%[/tex] interest annually. Assuming no deposits or withdrawals are made, which equation represents the amount of money in Josiah's account, [tex]y[/tex], after [tex]x[/tex] years?

A. [tex]y = 360(1.3)^x[/tex]
B. [tex]y = 360(0.3)^x[/tex]
C. [tex]y = 360(0.03)^x[/tex]
D. [tex]y = 360(1.03)^x[/tex]



Answer :

Let's start by understanding the parameters provided:
- Josiah's initial investment is \$360.
- The account accrues interest at an annual rate of 3%.

When dealing with compound interest, the formula to determine the amount of money in the account after [tex]\( x \)[/tex] years is given by:

[tex]\[ y = P(1 + r)^x \][/tex]

where:

- [tex]\( P \)[/tex] is the principal amount (the initial investment).
- [tex]\( r \)[/tex] is the annual interest rate (expressed as a decimal).
- [tex]\( x \)[/tex] is the number of years.
- [tex]\( y \)[/tex] is the amount of money in the account after [tex]\( x \)[/tex] years.

Let's assign the given values to this formula:
- [tex]\( P = 360 \)[/tex]
- [tex]\( r = 0.03 \)[/tex] (since 3% as a decimal is 0.03)
- [tex]\( x \)[/tex] is the variable representing the number of years.

Plugging these values into the formula, we get:

[tex]\[ y = 360(1 + 0.03)^x \][/tex]

Simplifying inside the parentheses:

[tex]\[ y = 360(1.03)^x \][/tex]

This equation represents the amount of money in Josiah's account after [tex]\( x \)[/tex] years.

Among the given options, the correct equation is:

[tex]\[ y = 360(1.03)^x \][/tex]

So, the correct answer is:

[tex]\[ y = 360(1.03)^x \][/tex]