Rita and Lumiere are solving a problem about driving to Scream N Barf theme park... They know that the theme park is 30 miles away and that they will drive an average of 15 miles per hour. They need to write an equation and solve it to find out how long it will take to get there. Rita says they should the formula `d=rt`, where `d` is the distance traveled in miles, `r` is the rate of speed in miles per hour, and `t` is the time in hours.

Lumiere says they should use the equation `t=\frac{d}{r}` instead. Who is right? Explain.