In a sale, all prices are reduced by 40%. Calculate the original price of an article whose sale price is $42.
Think: If prices are reduced by 40%, then the customer is paying 60% of the original cost. This 60% is $42 and we need to find the original price.
Let x be the original price of the article.
To develop a proportion for solving, say “60% is to 100% as $42 is to x” and write that in proportion form: $4595_w73_h38.png$
Cross-multiply to get a solvable equation: 60x=4200
Divide both sides by 60 to get 70. The original price was $70.