Hello,
Wendall travels for x hours, and Sarah travels for 6 more hours than Wendal, so
Sarah travels: (x+6) hours
Wendal's speed is: [tex]15 x\,\,\frac{mi}{h} [/tex]. Sarah travels 8 miles per hour less than Wendal, so:
Sarah's speed= [tex](15 x-8)\,\,\frac{mi}{h} [/tex]
[tex]d=v*t \\ d=(15x-8)(x+6) \\ d=15 x^{2}+90x-8x-48 \\ \boxed{d=15 x^{2} +82x-48}[/tex]
Answer: D