Question

Help me on either 16 or 17 explain how you did it

Answer 1

The .mp3 player finally sells for $99.00 .

Original price . . . $100 .

Increase the original price by 10% . 
(multiply by (100% + 10%)  =  110%  =  1.10)

                           (1.10) x ($100)  =  $110 .

Now decrease the $110 by 10% .
(multiply by (100% - 10%)  =  90%  =  0.90)

                           (0.90) x ($110)  =  $99 .