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View Full Version : travel problem: you leave at 12 @ 40mph; uncle leaves 2 hrs



hmwin
10-27-2008, 06:50 PM
Here's the question...

At noon, your family leaves Memphis traveling to Louisville at 40 mph. Your uncle leaves 2 hours later from Louisville to Memphis at 60 mph. He is taking the same route. The two cities are 380 miles apart. At what time do the cars meet?

My guess for the equation was for x=time for your family

40x + 60(x+2) = 380

where x = 2.6

does that mean they meet at around 4:30 pm?

Subhotosh Khan
10-27-2008, 07:17 PM
Here's the question...

At noon, your family leaves Memphis traveling to Louisville at 40 mph. Your uncle leaves 2 hours later from Louisville to Memphis at 60 mph. He is taking the same route. The two cities are 380 miles apart. At what time do the cars meet?

My guess for the equation was for x=time for your family

40x + 60(x+2) = 380 <<< Are you saying the uncle travel led for (x+2) hours?

If he started 2 hours LATER - how can he travel 2 MORE hours than the family did?

where x = 2.6

does that mean they meet at around 4:30 pm?<<< How is that?

hmwin
10-27-2008, 07:27 PM
Yes, I'm confused...

so would you say

40x + 60(x-2) = 380?

40x +60x-120 = 380

100x = 500

x=5

x-2 = 3 where they meet at 5 pm

Subhotosh Khan
10-27-2008, 07:41 PM
Yes, I'm confused...

so would you say

x-2 = 3 where they meet at 5 pm

I would say .... you are correct!!!

hmwin
10-27-2008, 07:46 PM
Then I would say...Thanks!

Denis
10-27-2008, 10:15 PM
You could do that one in your head hmwin:
when uncle leaves, family has already travelled 2 hours, or 80 miles: so they're 300 miles apart;
combined speed is 40+60= 100: 300 miles @ 100 mph = 3 hours...kapish?