A Fun Problem

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A Fun Problem

by centermass1976 » Mon Oct 06, 2008 4:32 pm
The correct answere is 10. However, I keep getting between 11.8 and 12. I don't know what gives?? Thanks--

A jogger running along a road at 5 kilometers per hour is overtaken
by a cyclist traveling at 30 kilometers per hour. If the cyclist stops
1 kilometer beyond where she passes the jogger, how many minutes after
the cyclist stops does the jogger reach her?

(A) 12
(B) 10
(C) 9
(D) 8
(E) 6
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by pre-gmat » Mon Oct 06, 2008 6:08 pm
cyclist overtakes jogger and stops after 1 km.

time taken for cyclist to travel that 1 km is 2 minutes.

Time taken by jogger to travel that extra 1 km is 12 minutes (traveling at 5km/hr)

so the jogger will reach after 12-2 = 10 minutes.

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by vishubn » Mon Oct 06, 2008 6:18 pm
Same approach !!

I guess mistake on ur side ! might be !

that u r calculating the time required for the jogger to reach the distance of 1 km ! covered !

but dont forget after he overtakes the jogger he will travel two mintues himself !!

sooo 1 km distance ... jogger will take 12 mins but he has already continued to jog for two mimutes

so answer will be 12-2-10

vishu

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by pre-gmat » Mon Oct 06, 2008 7:22 pm
You are right Vishubn.

but I dont understand what exactly you mean by this:

but dont forget after he overtakes the jogger he will travel two mintues himself

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by Sachindh » Mon Oct 06, 2008 8:31 pm
pre-gmat wrote:You are right Vishubn.

but I dont understand what exactly you mean by this:

but dont forget after he overtakes the jogger he will travel two mintues himself
Vishu meant - The moment Cyclist overtakes jogger, both (cyclist and jogger) travel in the same direction for 2 min whereas 2 min is the time to travel by cyclist to travel 1km from the point of overtake.

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by stop@800 » Mon Oct 06, 2008 8:31 pm
pre-gmat wrote:You are right Vishubn.

but I dont understand what exactly you mean by this:

but dont forget after he overtakes the jogger he will travel two mintues himself
For initial 1 KM
both jogger and cyclist are moving

cyclist stops after traveling 1km and joggers covers the remaining distance.

when cyclist was covering that 1 km distance
the jogger also covered some distance
so after cyclist stopped jogger need to cover distance = 1 km - distance covered by joggers [when cyclist was covering 1km]

as we need to find time required to cover remining distance.