Question 160932
"Steve traveled 600 miles at a certain speed" __ 600=rt __ 600/r=t


"Had he gone 20mph faster, the trip would have taken 1 hour less" __ 600=(r+20)(t-1) __ 600=rt+20t-r-20


substituting __ 600=(600)+20(600/r)-r-20 __ subtracting 600 __ 0=12000/r-r-20


multiplying by -r __ 0=r^2+20r-12000 __ factoring __ 0=(r+120)(r-100)


0=r+120 __ -120=r __ negative value not realistic


0=r-100 __ 100=r __ heavy foot