Dollar City is having an end-of-year sale, and all prices are being slashed. On the graph below, the $x$-axis represents the old price, and the $y$-axis represents the new sale price, in dollars.
Not to be outdone, Penny World, whose manager was a math major, has announced that all sale prices $(S)$ will be determined according to the equation :
$S=(0.15)P$,
where $P$ is the original price.
**Which store’s sale is better?**
[[☃ radio 1]]
