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Old Dec 28th 2009, 07:32 PM   #1
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Stucked!

A bus driver looks into a plane mirror 20 cm long which is placed 50 cm in front of him. If the rear window is 500 cm from the plane mirror, through what length of the rear window can he see whenever he looks into the mirror while driving?
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Old Dec 29th 2009, 06:40 PM   #2
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Waiting patiently for help!
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Old Dec 29th 2009, 10:36 PM   #3
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ans is 220 cm??
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Old Dec 30th 2009, 03:21 AM   #4
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I don't have the answer, neither do I know how to start with this problem.. How about you telling me how you got this answer and we shall discuss?
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Old Dec 30th 2009, 03:35 AM   #5
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image of window will be 500 cm behind the mirror. so distance from driver=500 +50 =550 cm.
next construct two straight lines originating from driver and grazing mirror endpoints and intersecting a portion of the image . find this portion using similarity ie.side proportionality.
10/x=50/550
and find 2x.
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Old Dec 30th 2009, 03:58 AM   #6
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Originally Posted by r.samanta View Post
image of window will be 500 cm behind the mirror. so distance from driver=500 +50 =550 cm.
next construct two straight lines originating from driver and grazing mirror endpoints and intersecting a portion of the image . find this portion using similarity ie.side proportionality.
10/x=50/550
and find 2x.
Do you mean drawing a diagram and drawing lines representing the light travel then get the answer?
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