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Rate: Average Speed of Traveling Train from A to B

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Rate: Average Speed of Traveling Train from A to B

by beeparoo » Sat Jun 28, 2008 6:59 pm
A train traveled 960 miles from Town A to Town B. What was the train's average speed during that journey?

1) If the train had traveled from Town A to Town B at an average speed that was 12 miles per hour slower, it would have taken 20 hours

2) If the train had traveled from Town A to Town B at an average speed that was 60 percent faster, it would have taken 6 fewer hours.
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Source: — Data Sufficiency |
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by wawatan » Sat Jun 28, 2008 8:31 pm
answer d

rt=960
(r-12)(t+20)=960

rt=960
1.6r *(t-6)= 960
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by beeparoo » Sat Jun 28, 2008 8:45 pm
wawatan wrote:answer d

rt=960
(r-12)(20)=960

rt=960
1.6r *(t-6)= 960
Hey wawatan, good job. The answer is D.

Just a small correction to one of your equations. My changes are in RED. It does not change the outcome, but I don't want to mislead earnest readers who need to learn how to set up equations.
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by llewellyn27 » Sun Jun 29, 2008 6:44 am
I think the answer should be A

RT = 960 ---given

They say if the train traveled 12 mph slower it would have taken 20 hrs

so R * 20 = 960

so R = 48

But actual R = 12 mph slower so R = 48 + 12 = 60

B is insuff

Please comment
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by beeparoo » Sun Jun 29, 2008 1:50 pm
llewellyn27 wrote:I think the answer should be A
...
B is insuff

Please comment
B is not insuff, it is SUFFICIENT, as I confirmed in my post above. In fact, wawatan has shown it in his/her calculations.

See above.
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by Gmatter2.0 » Mon Nov 16, 2009 9:30 pm
I think the answer should be A.
From 2) All we have is an equation in 2 variables time t and rate r.
How would we calculate r from the given information.

Am I missing something , please throw some light!....
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