12. Formula for simple interest = total= Principle(1+rate x time)
total = 4000 x (1+(0.35*4) = 4560.00
interest = total - principle: 4560- 4000 = $560.00
13. (5081.25 / 5000) ^(1/0.25) -1 = 0.0666 x 100 = 6.66%
14. a) 100 *1.06 = 106 after adding sales tax . 106 *0.1 = 10.60 ( 10% discount amount) 106 - 10.60 = $95.40 ( final price)
b) 100 x 0.10 = 10.00 ( 10% discount amount) 100-10 = 90.00. (price after discount) 90.00 x 1.06 = $95.40 ( final price)
they are both the same, neither one is a better deal
