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doki_pen
science forum beginner
Joined: 30 Jun 2005
Posts: 14
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 Posted: Wed Jun 28, 2006 4:40 am Post subject:
Word problem: Rate x time = distance
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Two cars leave Denver traveling in opposite directions. One car is
traveling at a speed of 80 km/hr and the other car at 96 km/hr. In how
many hours will the cars be 528 km apart? |
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UpChunky
science forum beginner
Joined: 03 Jun 2005
Posts: 36
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| Posted: Wed Jun 28, 2006 4:47 am Post subject:
Re: Word problem: Rate x time = distance
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"doki_pen" <doki_pen@yahoo.com> wrote in message
news:1151469608.484927.229500@b68g2000cwa.googlegroups.com...
| Quote: | Two cars leave Denver traveling in opposite directions. One car is
traveling at a speed of 80 km/hr and the other car at 96 km/hr. In how
many hours will the cars be 528 km apart?
|
t * 80 + t * 96 = 528 ?
t* (176) = 528 ?
t = 528 * 176 ?
t = 92,928 hours = 10.876 years ?
Better get started. |
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guenther.vonKnakspott@gmx
science forum Guru Wannabe
Joined: 24 Apr 2005
Posts: 250
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| Posted: Wed Jun 28, 2006 4:52 am Post subject:
Re: Word problem: Rate x time = distance
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doki_pen wrote:
| Quote: | Two cars leave Denver traveling in opposite directions. One car is
traveling at a speed of 80 km/hr and the other car at 96 km/hr. In how
many hours will the cars be 528 km apart?
Any of these two hints should help you solve this. |
a) What multiples of 6 have 8 as the least significant digit?
b) How far apart from each other are the cars after 1 hour?
Regards. |
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guenther.vonKnakspott@gmx
science forum Guru Wannabe
Joined: 24 Apr 2005
Posts: 250
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| Posted: Wed Jun 28, 2006 4:54 am Post subject:
Re: Word problem: Rate x time = distance
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Zodness wrote:
| Quote: | "doki_pen" <doki_pen@yahoo.com> wrote in message
news:1151469608.484927.229500@b68g2000cwa.googlegroups.com...
Two cars leave Denver traveling in opposite directions. One car is
traveling at a speed of 80 km/hr and the other car at 96 km/hr. In how
many hours will the cars be 528 km apart?
t * 80 + t * 96 = 528 ?
t* (176) = 528 ?
t = 528 * 176 ?
t = 92,928 hours = 10.876 years ?
Better get started.
If you are not going to help him, at least you should not mislead him. |
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Richard L. Hall
science forum beginner
Joined: 05 May 2006
Posts: 5
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| Posted: Wed Jun 28, 2006 5:09 am Post subject:
Re: Word problem: Rate x time = distance
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The cars are moving apart at a speed of 80 km/hr + 96 km/hr = 176 km/hr. So
after 1 hour, they will be 176 km apart. Now, it should now be easy to
figure out how long it takes for them to be 528 km apart.
--
Richard
http://www.richlh.com
Life is not a journey to the grave with the intention of arriving safely in
a pretty and well preserved body. Rather, it's to skid in broadside,
thoroughly used up, totally worn out, and loudly proclaiming "WOW! What a
Ride!" - Albert 'Skip' Rizzo (1954 - )
"doki_pen" <doki_pen@yahoo.com> wrote in message
news:1151469608.484927.229500@b68g2000cwa.googlegroups.com...
| Quote: | Two cars leave Denver traveling in opposite directions. One car is
traveling at a speed of 80 km/hr and the other car at 96 km/hr. In how
many hours will the cars be 528 km apart?
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Mike
science forum addict
Joined: 14 Oct 2005
Posts: 50
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| Posted: Wed Jun 28, 2006 5:56 am Post subject:
Re: Word problem: Rate x time = distance
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doki_pen wrote:
| Quote: | Two cars leave Denver traveling in opposite directions. One car is
traveling at a speed of 80 km/hr and the other car at 96 km/hr. In how
many hours will the cars be 528 km apart?
|
First we must figure out relative velocity. If v_1 = 80 and v_2 = 96
then the relative velocity is
v_rel = (v_1 + v_2)/(1 + (v_1v_2)/c^2)
Now you can work out the answer in the proper time of say car 1. For
better accuracy don't forget to take into account the gravitational
time dilation. |
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doki_pen
science forum beginner
Joined: 30 Jun 2005
Posts: 14
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| Posted: Wed Jun 28, 2006 6:04 am Post subject:
Re: Word problem: Rate x time = distance
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Rich,
That makes perfect sense, thank you so much!
Jon
Richard L. Hall wrote:
| Quote: | The cars are moving apart at a speed of 80 km/hr + 96 km/hr = 176 km/hr. So
after 1 hour, they will be 176 km apart. Now, it should now be easy to
figure out how long it takes for them to be 528 km apart.
--
Richard
http://www.richlh.com
Life is not a journey to the grave with the intention of arriving safely in
a pretty and well preserved body. Rather, it's to skid in broadside,
thoroughly used up, totally worn out, and loudly proclaiming "WOW! What a
Ride!" - Albert 'Skip' Rizzo (1954 - )
"doki_pen" <doki_pen@yahoo.com> wrote in message
news:1151469608.484927.229500@b68g2000cwa.googlegroups.com...
Two cars leave Denver traveling in opposite directions. One car is
traveling at a speed of 80 km/hr and the other car at 96 km/hr. In how
many hours will the cars be 528 km apart?
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UpChunky
science forum beginner
Joined: 03 Jun 2005
Posts: 36
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| Posted: Wed Jun 28, 2006 1:04 pm Post subject:
Re: Word problem: Rate x time = distance
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"guenther vonKnakspot" <apacur@gmail.com> wrote in message
news:1151470499.584940.284440@m73g2000cwd.googlegroups.com...
| Quote: |
Zodness wrote:
"doki_pen" <doki_pen@yahoo.com> wrote in message
news:1151469608.484927.229500@b68g2000cwa.googlegroups.com...
Two cars leave Denver traveling in opposite directions. One car is
traveling at a speed of 80 km/hr and the other car at 96 km/hr. In how
many hours will the cars be 528 km apart?
t * 80 + t * 96 = 528 ?
t* (176) = 528 ?
t = 528 * 176 ?
t = 92,928 hours = 10.876 years ?
Better get started.
If you are not going to help him, at least you should not mislead him.
|
he was helped over the hill, on a simple problem, and should easily spot the
minor intentional problem of division/multiplication.
Actually "opposite directions" is not exactly 180 degrees apart and could be
a good source of error. |
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