Mph - writing and solving equations

Question

Gabrielle and Ashton both leave the bookstore at the same time, but in opposite directions. If Ashton travels 8 mph faster than Gabrielle and after 4 hours they are 104 miles apart, how fast is each traveling?

Answer 1

(x+x+8) * 4 = 104

(2x+8)*4 = 104

2x+8 = 104/4 = 52/2 = 26

2x = 18

x=9

9 mph and 17 mph