Carmen has $90 in a savings account that earns 10% interest per year. The interest is no compounded. How much interest will she earn in 3 years?

Question

Use the formula i = prt, where i is the interest earned, p is the principal (starting amount), r is the interest rate expressed as a decimal, and t is the time in years.

Answer 1

To calculate the interest Carmen will earn in 3 years, we can use the formula:

\[ i = prt \]

where:

• \( p \) is the principal (starting amount) = $90
• \( r \) is the interest rate = 10% = 0.10 (as a decimal)
• \( t \) is the time in years = 3 years

Now, substituting in the values:

\[ i = 90 \times 0.10 \times 3 \]

Calculating that:

1. First, calculate \( 90 \times 0.10 \): \[ 90 \times 0.10 = 9 \]

2. Then multiply that by 3: \[ 9 \times 3 = 27 \]

So, the interest earned in 3 years will be: \[ i = 27 \]

Carmen will earn $27 in interest in 3 years.