Answer:
13.5
Step-by-step explanation:
12/4=3
9/3=3
4.5x3=13.5
OK so first I like to find what 10% is which in this case would be 1.8 and to find the other 5% you divide 1.8 by 2 which gets you .9 if you and 1.8 and .9 you get 2.7 and if you add 2.7 to 18 you get 20.7 which is your retail price
First you compare the denomonators and see if they have any common multiples, then what you do to one side you do to the other so you multiply so you get the same number on both denomonators.finally you multipybthe same number you did ti he botto. to the top.p.s. your welcome