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Difficult Math Question #54 - Rates

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Difficult Math Question #54 - Rates

by 800guy » Wed Nov 15, 2006 5:33 pm
Two people walked the same distance, one person's speed is between 25 and 45,and if he used 4 hours, the speed of another people is between 45 and 60,and if he used 2 hours, how long is the distance?

A.116
B.118
C.124
D.136
E.140
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Re: Difficult Math Question #54 - Rates

by kulksnikhil » Wed Nov 15, 2006 6:35 pm
800guy wrote:Two people walked the same distance, one person's speed is between 25 and 45,and if he used 4 hours, the speed of another people is between 45 and 60,and if he used 2 hours, how long is the distance?

A.116
B.118
C.124
D.136
E.140

A and B both are satisfying the ranges (25~45 and 45~60) :roll:
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OA

by 800guy » Fri Nov 17, 2006 10:33 am
here's the suggested OA:

First person-- speed is between 25mph and 45mph
so for 4 hrs he can travel 100 miles if he goes at 25mph speed
and for 4 hrs he can travel 130 miles if he goes at 45 mph speed

similarly

Second person-- speed is between 45mph and 60mph
so for 2 hrs he can travel 90 miles if he goes at 45mph speed
and for 2 hrs he can travel 120 miles if he goes at 60 mph speed

So for the first person---distance traveled is greater than 100 and Less than 130

and for the second person---distance traveled is greater than 90 and less than 120

so seeing these conditions we can eliminate C, D, and E answers...

but I didn’t understand how to select between 116 and 118 as both these values are satisfying the conditions...
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by 800guy » Fri Nov 17, 2006 10:33 am
yeah this was a poorly written question
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by hishighness » Fri Dec 08, 2006 7:48 am
See the main logic is they both have to cover the same distance and one should take take half the time taken by other persson .. which means speed of one should be double the speed of other person Between 25-45 and 45-60 double speed combos can be

25,50
26,52
27,54
28,56
29,58
30,60

Now see the choices --- Only 116 is in choice
100,104,108,112,120 are not in choices
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by 800guy » Fri Dec 08, 2006 10:29 am
hishighness wrote:See the main logic is they both have to cover the same distance and one should take take half the time taken by other persson .. which means speed of one should be double the speed of other person Between 25-45 and 45-60 double speed combos can be

25,50
26,52
27,54
28,56
29,58
30,60

Now see the choices --- Only 116 is in choice
100,104,108,112,120 are not in choices

thanks for the clarification!!
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by Stuart@KaplanGMAT » Wed Nov 26, 2008 5:32 pm
hishighness wrote:See the main logic is they both have to cover the same distance and one should take take half the time taken by other persson .. which means speed of one should be double the speed of other person Between 25-45 and 45-60 double speed combos can be

25,50
26,52
27,54
28,56
29,58
30,60

Now see the choices --- Only 116 is in choice
100,104,108,112,120 are not in choices
To dredge up old wounds (since someone reposted) - nowhere does it say the rates have to be integers!
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