Answer: $15
The original price of the mirror is unknown, so let's call it x.
The discount on the original price is a 20% discount, so it is 20% of x, or 0.2x.
We are told the discount is $3, so 0.2x = 3. Now we solve the equation for x.
0.2x = 3
Divide both sides by 0.2.
x = 3/0.2
x = 15
The regular price is $15.
Explanation: