Find principal amount at 5.6% for 4 years totaling 145.60

$118.95

Step-by-step explanation:

Assuming simple increase:

Use the equation for amount for simple interest

A = P(1 + rt)

A is the total at the end of the time period.

r is the rate of interest in decimal form.

t is the time period length.

P is the principal amount.

Substitute values we know into the equation

5.6% in decimal form is 0.056

A = P(1 + rt)

145.60 = P(1 + (0.056)(4))

Simplify

145.60 = P(1.224)

Isolate P

P = 145.60/1.224

P ≈ 118.95   (Not equal because rounded to 2 decimal places)

The principal amount is $118.95.