The equation [tex]$A = 2,400\left(1 + \frac{0.031}{4}\right)^{4t}$[/tex] represents the amount of money earned on a compound interest savings account. What does the value 0.031 represent?

A. The value 0.031 represents the interest rate, which means the annual compounded interest rate is [tex]3.1\%[/tex].
B. The value 0.031 represents the interest rate, which means the annual compounded interest rate is [tex]0.31\%[/tex].
C. The value 0.031 represents the investment period, which means the investment is invested for 0.031 years.
D. The value 0.031 represents the investment period, which means the investment is invested for 3.1 years.



Answer :

The value [tex]\( 0.031 \)[/tex] in the equation [tex]\( A = 2,400 \left( 1 + \frac{0.031}{4} \right)^{el} \)[/tex] represents the annual interest rate. Let's break it down in detail:

1. Equation Explanation: The given equation is for calculating the future amount [tex]\( A \)[/tex] in a compound interest scenario. The formula for compound interest can be expressed as:
[tex]\[ A = P \left( 1 + \frac{r}{n} \right)^{nt} \][/tex]
where:
- [tex]\( P \)[/tex] is the principal amount (initial investment),
- [tex]\( r \)[/tex] is the annual interest rate,
- [tex]\( n \)[/tex] is the number of times interest is compounded per year,
- [tex]\( t \)[/tex] is the time in years,
- [tex]\( A \)[/tex] is the amount of money accumulated after [tex]\( t \)[/tex] years, including interest.

2. Interpretation of Variables:
- In the given equation [tex]\( A = 2,400 \left( 1 + \frac{0.031}{4} \right)^{el} \)[/tex],
- The principal amount [tex]\( P \)[/tex] is [tex]\( 2,400 \)[/tex] dollars.
- The term [tex]\(\frac{0.031}{4}\)[/tex] indicates that the annual interest rate [tex]\( r \)[/tex] is [tex]\( 0.031 \)[/tex], and it is compounded quarterly ([tex]\( n = 4 \)[/tex]).
- The exponent [tex]\( el \)[/tex] appears to replace [tex]\( nt \)[/tex], suggesting some substitution was made there and needs further context.

3. Identifying the Annual Interest Rate:
- The value [tex]\( 0.031 \)[/tex] specifically is found in the fraction [tex]\(\frac{0.031}{4}\)[/tex], which corresponds to the interest rate divided by the number of compounding periods per year ([tex]\( n = 4 \)[/tex]).
- This clearly establishes that [tex]\( 0.031 \)[/tex] is the annual interest rate.

4. Converting to Percentage:
- To express the annual interest rate as a percentage, multiply [tex]\( 0.031 \)[/tex] by 100.
[tex]\[ 0.031 \times 100 = 3.1\% \][/tex]

Therefore, the value [tex]\( 0.031 \)[/tex] represents the annual interest rate. When expressed as a percentage, the annual compounded interest rate is [tex]\( 3.1\% \)[/tex].

Thus, the correct interpretation from the choices provided is:

The value [tex]\( 0.031 \)[/tex] represents the interest rate, which means the annual compounded interest rate is [tex]\( 3.1\% \)[/tex].