Respuesta :

If it includes the 5% tax, this means that $22.05 is 105% of the original price.

Let's set up a proportion.

22.05/105 = x/100

100*1.05=105
x*1.05=22.05

Divide both sides by 1.05
x=21

Final answer: $21
$21.00

x + .05x = 22.05
1.05x = 22.05
   x = 22.05/1.05
   x  = $21.00