Car A and car B both travel 560 miles Car A drove at an aver

Car A and car B both travel 560 miles. Car A drove at an average speed of 10 miles per hour faster than car B and made the trip in one hour less time. Find the average speeds of both cars.

Solution

st=d
Let:
s=B\'s speed
t=A\'s time
.
A) t(s+10)=560
B) s(t+1)=560
.
ts+10t=ts+s
10t=s
.
A)
t(10t+10)=560
10t^2+10t-560=0
t^2+t-56=0 Divide each side by 10
(t+8)(t-7)=0
t=7 hrs for A
.
B)
s(7+1)=560
s=70 mph for B
s+10=80 mph for A