Two trucks leave a warehouse at the same time one travels do north at an average of 51 mph and the other travels due south at this average speed of 64 per hour after how many hours will the two trucks be 517.5 miles apart

This would be the initial equation because, after a certain amount of t time, the fastest truck will be 517. mi apart from the slowest truck. Let's solve the equation
[tex]\begin{gathered} t(64mi/h\text{ - }51mi/h)=517.5mi \\ t(13mi/h)=517.5mi \\ t=\frac{517.5mi}{13mi/h} \\ \\ t=39.81h \end{gathered}[/tex]After 39.81h the trucks will be apart 517.5 mi