Question 286906
Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r

In 3.5 hours your friend has driven 3.5*60=210 mi leaving 450-210=240 for you to drive  If you want to reach your hotel in 4 mores hours, your rate (or average speed) must be 240/4=60mph

So 7.5 hours at an average speed of 60 mph=450 mi

Hope this helps---ptaylor