The equation [tex]$A=P(1+0.037 t)$[/tex] represents the amount of money earned on a savings account with [tex]3.7\%[/tex] annual simple interest. If the amount after 5 years is equal to [tex]\$1,422[/tex], what is the amount of the principal investment?

A. [tex]\$1,200[/tex]
B. [tex]\$1,422[/tex]
C. [tex]\$274.25[/tex]
D. [tex]\$294.86[/tex]



Answer :

To determine the principal investment given the final amount after 5 years and an annual simple interest rate of 3.7%, we can follow these steps:

1. Identify the given variables:
- Final amount ([tex]\( A \)[/tex]) after 5 years: \[tex]$1,422 - Annual simple interest rate (\( r \)): 3.7% (expressed as a decimal, 0.037) - Time duration (\( t \)): 5 years 2. Write down the formula for the total amount in a simple interest context: \[ A = P(1 + rt) \] Where: - \( P \) is the principal amount (initial investment) - \( r \) is the annual interest rate in decimal form - \( t \) is the time in years - \( A \) is the amount after \( t \) years 3. Substitute the known values into the equation: \[ 1422 = P(1 + 0.037 \times 5) \] 4. Simplify inside the parentheses: \[ 1422 = P(1 + 0.185) \] \[ 1422 = P(1.185) \] 5. Solve for the principal amount \( P \): \[ P = \frac{1422}{1.185} \] 6. Perform the division: \[ P \approx 1200.0 \] Thus, the principal investment amount is approximately \$[/tex]1,200.

Therefore, the correct answer is:
[tex]\[ \$1200 \][/tex]