5.2 Exercise 93

Stephanie left Riverside, California, driving her motorhome north on Interstate 15 towards Salt Lake City at a speed of 56 miles per hour. Half an hour later, Tina left Riverside in her car on the same route as Stephanie, driving 70 miles per hour. Solve the system $\begin{cases} 56 s = 70 t \\ s = t + \frac{1}{2} \end{cases}$.

1. ⓐ for $t$ to find out how long it will take Tina to catch up to Stephanie.
2. ⓑ what is the value of $s$, the number of hours Stephanie will have driven before Tina catches up to her?