Practice solving and using literal equations.

The formula for simple interest is [tex]\( I = P \cdot r \cdot t \)[/tex], where:
- [tex]\( I \)[/tex] represents the simple interest,
- [tex]\( P \)[/tex] is the principal amount,
- [tex]\( r \)[/tex] is the interest rate,
- [tex]\( t \)[/tex] is the time in years.

Isolate [tex]\( P \)[/tex] from the equation: [tex]\( P = \frac{I}{r \cdot t} \)[/tex].

Using this formula, what is the principal amount [tex]\( P \)[/tex] that will generate [tex]$20 at a 5% interest rate over 5 years?

\( \text{Answer: } \$[/tex] \)



Answer :

Certainly! To solve for the principal amount [tex]\( P \)[/tex] that will generate [tex]$20 in interest at a 5% interest rate over 5 years, we use the formula for simple interest and solve for \( P \). The given formula for simple interest is \( I = Prt \), where: - \( I \) is the interest earned, - \( P \) is the principal amount, - \( r \) is the interest rate, - \( t \) is the time period in years. First, isolate \( P \) in the formula: \[ I = Prt \] By rearranging the equation to solve for \( P \), we divide both sides by \( rt \): \[ P = \frac{I}{rt} \] Now, we use the given values: - \( I = 20 \) (the interest earned), - \( r = 0.05 \) (the interest rate as a decimal), - \( t = 5 \) (the time in years). Substituting these values into the equation: \[ P = \frac{20}{0.05 \times 5} \] Calculating the denominator first: \[ 0.05 \times 5 = 0.25 \] Now, divide the numerator by the denominator: \[ P = \frac{20}{0.25} \] Which simplifies to: \[ P = 80 \] Therefore, the amount of money, \( P \), that will generate $[/tex]20 at a 5% interest rate over 5 years is $80.