The answer is 44.
40 / 100 = 0,4 * 10 = 4 (10%)
40 + 4 = 44
The answer is 21x-25 because all you have to do is multiply the 1/4 by the 84x and then multiply 1//4 by negative 100. A simpler way of explaining this is just that you need to distribute
$16,744.00
Link: http://www.moneychimp.com/features/simple_interest_calculator.htm
6x=16
÷6 both sides
x=16/6 or 8/3
