How do you do this word problem...I have no idea?

Question

You and a friend each drive 50.0 km. You travel at 90 km/h; your friend travels at 95.0 km/h. How long will your friend wait for you at the end of the trip?

I'm not even sure where to start with this problem...

Answer 1

Distance...time...rate problem....d = rt

Let your friend be: d = rt

Let you be: D = RT

d = D = 50 km (you both travel the same dist)

Your speed (R) = 90 km/hr
Your friend's speed (r) = 95.0 km/hr


Your friend's time:
d = rt
==> t = d/r = 50/95 = 0.53 hrs

Your time:
D = RT
==> T = D/R = 50/90 = 0.56 hrs

So, your friend gets there in 0.53 hrs...you get there in 0.56 hrs.

Your friend is waiting: T - t = 0.03 hrs, which is 0.03*60 = 1.8 minutes.

Make sense? I left off some units, but that's so the arithmetic is a little more clear. You need to include the units everywhere! :)

Hope this makes sense to you.

Answer 2

You have a set distance and a speed that both you and your friend are traveling.

Remember that Time = Distance / Speed

Find the travel time for both you and your friend.

The difference between the two is how long your friend will wait for you.