Mr. Smith went to visit his daughter. The trip took 7 hours. On the return trip he went by a scenic route which was 20 minutes longer. He drove 5 mph slower and it took him 8 hours. How far did Mr. Smith drive?

Question

jamesj · Answer

Let x1 be the distance and v1 the first speed.  Then 7v1 = x1.

On the return trip the distance is x2 = x1 + 20 and v2 = v1 - 5.  
Then 8v2 = x2 => 8(v1-5) = x1 + 20

You now have two equations in the unknowns v1 and x1.  Solve them.

Let me know if you get stuck.

anonymous · Answer

I found 860 from that

anonymous · Answer

Everything makes sense except the x2 = x1 + 20. Doesn't the 20 need to be multiplied by some rate to make it a distance?

jamesj · Answer

Oh, sorry yes.   x2 = x1 + (20/60)v2   , the /60 is to convert it into hours

anonymous · Answer

ah, thank you very much! That helped me a lot

jamesj · Answer

So x2 = x1 + (1/3)(v1 - 5)