Question 1112209
Simple Interest = (Principal * Number of years * Rate of interest)/100

From the given information, we can write:
                
             $729   = (Principal * 4 * 2)/100

That is,
        $729 * 100  = (Principal * 4 * 2)
Thus,
         Principal  = ($729 * 100)/(4 * 2)
                    = $9112.5