Questions: Solve for the missing item in the following.
Note: Do not round intermediate calculations. Round your answer to the nearest whole percent.
Principal Interest rate Time Simple interest
5,400 % 19 months 342
Transcript text: Solve for the missing item in the following.
Note: Do not round intermediate calculations. Round your answer to the nearest whole percent.
\begin{tabular}{|c|c|c|c|c|c|}
\hline \multicolumn{2}{|l|}{ Principal } & Interest rate & Time & \multicolumn{2}{|l|}{ Simple interest } \\
\hline \$ & 5,400 & \% & 19 months & \$ & 342 \\
\hline
\end{tabular}
Solution
Solution Steps
To find the missing interest rate in a simple interest problem, we can use the formula for simple interest: \( I = P \times r \times t \), where \( I \) is the interest, \( P \) is the principal, \( r \) is the interest rate, and \( t \) is the time in years. We need to solve for \( r \). First, convert the time from months to years. Then, rearrange the formula to solve for \( r \) and calculate it using the given values.
Step 1: Identify the Known Values
We are given the principal amount \( P = 5400 \), the simple interest \( I = 342 \), and the time in months \( t = 19 \).
Step 2: Convert Time to Years
Since the time is given in months, we need to convert it to years. The conversion is done by dividing the number of months by 12:
\[
t = \frac{19}{12} \approx 1.5833 \text{ years}
\]
Step 3: Use the Simple Interest Formula
The formula for simple interest is:
\[
I = P \times r \times t
\]
We need to solve for the interest rate \( r \). Rearranging the formula gives:
\[
r = \frac{I}{P \times t}
\]
Step 4: Calculate the Interest Rate
Substitute the known values into the formula:
\[
r = \frac{342}{5400 \times 1.5833} \approx 0.0400
\]
Convert the interest rate to a percentage by multiplying by 100:
\[
r = 0.0400 \times 100 = 4.00\%
\]