472.50 for one years interest.
The simple interest is calculated with
Where represents the final amount of money, is the principal, is the interest rate in decimal number and is the time.
So, from the problem, we have
Replacing these values, we have
This means Marian has to pay $472.50
The formula for determining simple interest is expressed as
I = PRT/100
I represents interest paid on the amount of money borrowed.
P represents the principal or amount of money borrowed.
R represents interest rate
T represents the duration in years.
From the given information,
P = $450
R = 5%
T = 1 year
I = (450 × 5 × 1)/100
I = $22.5
the total amount that she pays for the Soundsystem is
450 + 22.5 = $472.5
b.) 160 miles on a 5 gallons car
168/6= 28 miles/gallon
32 miles/gallon is the most amount, so this is the best.