Simple Interest: The sum of $400.50 is invested at interest rate 12% for 4 years. Find the simple interest for the period and the final amount on the investment.
 Simple Interest = Principal x Rate x Time
                        = 400.50 x (12/100) x 4
                        = $192.24.
 The final amount is the Interest + Principal = 192.24 + 400.50 =
$592.74