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CEO
Joined: 21 Jan 2007
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Location: New York City
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On level farmland, two runners leave at the same time from [#permalink]
 02 Jun 2007, 17:59
Question Stats:
0% (00:00) correct
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9. On level farmland, two runners leave at the same time from the intersection of two country roads. One runner jogs due north at a constant rate of 8 miles per hour while the second runner jogs due east at a constant rate that is 4 miles per hour faster than the first runner's rate. How far apart, to the nearest mile, will they be after 1/2 hour ?
(A) 6
(B) 7
(C) 8
(D) 12
(E) 14
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CEO
Joined: 17 May 2007
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If runner 1 is going north and runner 2 is going east they are like two sides of a 90 degree triangle.
Side 1 = 8 m/h --> 4 m in 1/2 hr
Side 2 = 12 m/h --> 6 m in 1/2 hr
to complete this right angle triangle
d^2 = 4^2 + 6^2
d^2 = 52
= 2 sqrt(13) ~ 7
Answer option B
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Director
Joined: 25 Oct 2006
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Let ABC is a right angle triangle, and angle ABC is 90 degree, So, first one is going through AB and achieved 4miles whereas the person on BC achieves 6 miles in half an hour,
Now sqrt(4^2 + 6^2) = nearest distance ~ 7 B.
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