After a discount of 20 %, Marjorie paid $ 180 for a dress. The original price of the dress was​

Explanation:

x = original price

If she saves 20%, then she still pays the remaining 80% which then converts to the decimal form 0.80

The expression 0.80x represents the new price, or sale price, of the dress. We're told this price is $180

Equate the two expressions and solve for x

0.80x = 180

x = 180/0.80

x = 225

The original price is $225

Checking the

20% of 225 = 0.20*225 = 45

She saves $45

225 - 45 = 180

This confirms the answer.