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astheris
Aug 9, 2012, 02:02 PM
You and a friend each drive 50.0 km. you travel at 90 km/h; your friend travels at 95.0km/hr. how long will your friend have to wait for you at the end of the trip

pianobuggy
Aug 9, 2012, 04:50 PM
This sounds like a homework question, so I'll give you a hint of how to solve it instead of the answer.
You need the time it will take you friend, and the time it takes you, then subtract.
How do you get the time? In physics we have a term called "dimensional analysis" which is just a fancy way of saying that you can get the answers by looking at the units. You have a value that is in km and a value that is in km/hr. You want a unit of time, like hours. So if you have km and km/hr, how can you get hours? You divide km by km/hr! (or just multiply by the inverse... km x hr/km, the km cancel and you get hrs out) This tells you how to solve the problem - you just need to put the numbers in there. Be sure that when you divide by km/hr you divide the number.
Does that help? Let me know if you need a better explanation.

kakkarod
Aug 17, 2012, 02:36 AM
95 km/hr person will reach there in 18.94 min

90km/hr person will reach tjere in 20 min...

(plss cross check)