Back in the day of analog recording tape, Amalgamated Colgate Enterprises had a sale. Professional quality tape dropped from $30 to $28 per reel, and regular quality tape dropped from $24 to $23 per reel. The Bethel Recording Studio normally spent $1440 per week on tape, 3/4 of which was used for professional quality tape. How much did they save during each week of the sale?
Solution
Bethel Recording studio normally spent 3/4 of $1440, or $1080, per week on professional quality tape. At $30 per reel, they bought 36 reels per week. They spent the remaining $360 on 15 regular quality reels per week. Since they saved $2 per reel on the professional quality tape and $1 per reel on regular quality tape, they saved 2(36) + 1(15) = 72 + 15 = $87 per week during the sale.
(Colgate Enterprises, so named, is in homage to Colgate toothpaste, which, in a great innovation back in the day, put the opening of its toothpaste tubes as tiny slits—rectangles if you will—rather than round holes. Their commercial went "Comes out like a ribbon, lies flat on the brush." The toothpaste was withdrawn from the market in 1979 but was reintroduced later and apparently is a best-seller in Turkey. The Wikipedia article does not mention how it now comes out of the tube.)