Question

It took Brian 6 hours to drive to the sales conference. He took the same route on the way back home, but

thus time the trip took 7 hours. If Brian drove 9 mph faster on his way to the conference, how fast did he
drive on the way back home?

Answer 1

Answer: 54 mph

Explanation:

d-the distance

s+9 - the speed to the conference

d=6*(s+9)

s- is the speed on the way back home

d=7*s

so 6*(s+9)=7*s

6s+54=7s

-6s -6s

54= 7s-6s

s=54 mph