Data $1-2-3$ is a top$-$selling electronic spreadsheet product. Data is about to release version $5\mathrm{.}0.$ It divides its customers into two groups: new customers and upgrade customers $($those who previously purchased Data $1-2-3,4\mathrm{.}0$ or earlier versions$).$ Although the same physical product is provided to each customer group, sizable differences exist in selling prices and variable marketing costs: