An investment earning simple interest at a rate of 1.10% per annum for a term of 5 years earned $82.50 in interest. What was the principal?

5 * .011 * p = 82.5

To find the principal, we need to use the formula for calculating simple interest:

Simple Interest = Principal × Rate × Time

In this case, we are given the simple interest earned ($82.50), the interest rate (1.10% per annum), and the time period (5 years). We need to find the principal.

Let's plug in the given values into the formula and solve for the principal:

$82.50 = Principal × 1.10% × 5

First, convert the interest rate from a percentage to a decimal by dividing it by 100:

1.10% ÷ 100 = 0.011

Substitute the decimal value back into the formula:

$82.50 = Principal × 0.011 × 5

Simplify the equation:

$82.50 = 0.055 × Principal

Now, isolate the Principal by dividing both sides of the equation by 0.055:

$82.50 ÷ 0.055 = Principal

Calculating this gives us:

$1500 = Principal

Therefore, the principal amount is $1500.