recall d = rt, distance = rate * time.
now, he has a speed rate of 56 mph for a distance of 504
[tex]\bf d=rt\implies 504=56t\implies \cfrac{504}{56}=t\implies \stackrel{hours}{9}=t[/tex]
so, at that speed the whole driving time is 9 hours then. Ok, he drove 2 hours today, that means he drove 7 yesterday, 9 - 2.
how many miles is it for 7 hours at 56mph? d = rt ---> d = 56 * 7
that many miles he drove yesterday.
