A principal amount of [tex]\$200[/tex] is placed in a savings account with an annual rate of [tex]3.75\%[/tex] simple interest for 6 years. Which formula would correctly determine the final amount?

A. [tex]A = (200)(0.0375)(6)[/tex]
B. [tex]A = (200)(3.75)(6)[/tex]
C. [tex]A = (200)(0.0375)(6) + 200[/tex]
D. [tex]A = (200)(3.75)(6) + 200[/tex]



Answer :

To determine the final amount in a savings account that earns simple interest, we use the formula:

[tex]\[ A = P + I \][/tex]

where:
- [tex]\( P \)[/tex] is the principal amount (initial investment),
- [tex]\( I \)[/tex] is the interest earned over a period of time.

Simple interest can be calculated using the formula:

[tex]\[ I = P \cdot r \cdot t \][/tex]

where:
- [tex]\( I \)[/tex] is the simple interest,
- [tex]\( P \)[/tex] is the principal amount,
- [tex]\( r \)[/tex] is the annual interest rate (as a decimal),
- [tex]\( t \)[/tex] is the time the money is invested for, in years.

Given the problem:
- The principal amount [tex]\( P \)[/tex] is \$200,
- The annual interest rate [tex]\( r \)[/tex] is [tex]\(3.75\% = 0.0375\)[/tex] (as a decimal),
- The time [tex]\( t \)[/tex] is 6 years.

First, we calculate the simple interest [tex]\( I \)[/tex]:

[tex]\[ I = 200 \cdot 0.0375 \cdot 6 = 45 \][/tex]

Next, we determine the final amount [tex]\( A \)[/tex]:

[tex]\[ A = 200 + 45 = 245 \][/tex]

Therefore, the correct formula to determine the final amount is:

[tex]\[ A = (200)(0.0375)(6) + 200 \][/tex]

This matches the third option in the list:

[tex]\[ A = (200)(0.0375)(6) + 200 \][/tex]