Question

interest?

1. \tif you borrow $225 for eight years at an interest rate of 6%, how much interest will you pay?
2. \tif the balance at the end of eight years on an investment of $230 that has been invested at a rate of 3% is $285.20, how much was the interest?

\thow much interest does a $407 investment earn at 6% over seven years?
\tinterest rate of 3%, how much

Explanation:

Let's solve each problem one by one using the simple interest formula \( I = P \times r \times t \), where \( I \) is the interest, \( P \) is the principal amount, \( r \) is the annual interest rate (in decimal), and \( t \) is the time in years.

Problem 5:

Step 1: Identify the values
\( P = \$225 \), \( r = 6\% = 0.06 \), \( t = 8 \) years.

Step 2: Apply the simple interest formula
\( I = 225 \times 0.06 \times 8 \)
First, calculate \( 225 \times 0.06 = 13.5 \)
Then, \( 13.5 \times 8 = 108 \)

Problem 6:

Step 1: Recall the relationship
The balance \( A \) is the sum of the principal \( P \) and the interest \( I \), so \( I = A - P \).

Step 2: Identify the values
\( A = \$285.20 \), \( P = \$230 \)

Step 3: Calculate the interest
\( I = 285.20 - 230 = 55.20 \)

Problem (the last one):

Step 1: Identify the values
\( P = \$407 \), \( r = 6\% = 0.06 \), \( t = 7 \) years.

Step 2: Apply the simple interest formula
\( I = 407 \times 0.06 \times 7 \)
First, calculate \( 407 \times 0.06 = 24.42 \)
Then, \( 24.42 \times 7 = 170.94 \)

Answer:

s:

• Problem 5: \(\$108\)
• Problem 6: \(\$55.20\)
• Last problem: \(\$170.94\)