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The figure above shows the present position on a radar [#permalink]
 16 May 2008, 17:37
Question Stats:
44% (01:31) correct
55% (00:34) wrong based on 2 sessions
Attachment: 
Radar.jpg [ 2.9 KiB | Viewed 1965 times ]
The figure above shows the present position on a radar screen of a sweeping beam that is rotating at a constant rate in a clockwise direction. In which of the four quadrants will the beam lie 30 seconds from now ? (1) In each 30-second period, the beam sweeps through 3.690° (2) r = 40
Last edited by Bunuel on 15 Feb 2013, 02:22, edited 1 time in total.
Renamed the topic and edited the question.
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goalsnr wrote: 9. The figure above shows the present position on a radar screen of a sweeping beam that is rotating at a constant rate in a clockwise direction. In which of the four quadrants will the beam lie 30 seconds from now ?
(1) In each 30-second period, the beam sweeps through 3.690°
(2) r = 40
Please see attached document for teh diagram. From what I see, the answer would be A. The current position of the Radar beam is somewhere in the middle of the first quadrant and it moves only 3.690degrees, which would still be well within 90degrees. Statement 2 by itself can't offer much since it doesn't tell you the rate of movement. What's the OA?
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I don't think that we can assume from the first statement that r>3.69
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To answer this question, we need to know the current position of the beam (i.e r) and we need to know the rate of rotation
1) gives us rate of rotation only, insuff
2) gives us r=40 degrees, insuff
1)2). in 30 seconds, the beam will be in q1, with r = 40-3.69
The answer is C
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buffdaddy wrote: To answer this question, we need to know the current position of the beam (i.e r) and we need to know the rate of rotation
1) gives us rate of rotation only, insuff
2) gives us r=40 degrees, insuff
1)2). in 30 seconds, the beam will be in q1, with r = 40-3.69
The answer is C I think The rate of rotation in Statement 1 is enough to answer the question because the image shows the radar bear somewhere in the middle of the 1st Quadrant (near around 45degrees). Statement 2 simply reaffirms the position of the beam within the 2nd quadrant. Can someone confirm the OA?
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wizardofwashington wrote: buffdaddy wrote: To answer this question, we need to know the current position of the beam (i.e r) and we need to know the rate of rotation
1) gives us rate of rotation only, insuff
2) gives us r=40 degrees, insuff
1)2). in 30 seconds, the beam will be in q1, with r = 40-3.69
The answer is C I think The rate of rotation in Statement 1 is enough to answer the question because the image shows the radar bear somewhere in the middle of the 1st Quadrant (near around 45degrees). Statement 2 simply reaffirms the position of the beam within the 2nd quadrant. Can someone confirm the OA? But no where its mentioned teh diagram is drawn to scale. The OA is A. But I diagree fo rthe same reason I mentioned in my previous sentence. C makes sense.
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goalsnr wrote: 9. The figure above shows the present position on a radar screen of a sweeping beam that is rotating at a constant rate in a clockwise direction. In which of the four quadrants will the beam lie 30 seconds from now ?
(1) In each 30-second period, the beam sweeps through 3.690°
(2) r = 40
Please see attached document for teh diagram. To rephrase this question, is the beam with r deg still in the same quadrant? Statement (1) alone gives us the speed and degree of the movement of the beam every 30-second period. Sufficient for us to know whethere the beam is. Eliminate B, C and E. Statement (2) alone tells us r = 40. But not where it can be 30 seconds from now. Not sufficient. Eliminate D. Ans: A
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fresinha12 wrote: what is the source of this question? DS section 19, question number 9. The DS section are part of the 1000 question series
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jimmylow wrote: goalsnr wrote: 9. The figure above shows the present position on a radar screen of a sweeping beam that is rotating at a constant rate in a clockwise direction. In which of the four quadrants will the beam lie 30 seconds from now ?
(1) In each 30-second period, the beam sweeps through 3.690°
(2) r = 40
Please see attached document for teh diagram. To rephrase this question, is the beam with r deg still in the same quadrant? Statement (1) alone gives us the speed and degree of the movement of the beam every 30-second period. Sufficient for us to know whethere the beam is. Eliminate B, C and E. Statement (2) alone tells us r = 40. But not where it can be 30 seconds from now. Not sufficient. Eliminate D. Ans: AIn which of the four quadrants will the beam lie 30 seconds from now ?We have no information regarding the current position.
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The figure above shows the present position on a radar screen of a sweeping beam that is rotating at a constant rate in a clockwise direction. In which of the four quadrants will the beam lie 30 seconds from now ? (1) In each 30-second period, the beam sweeps through 3.690° (2) r = 40 Not sure if there's a typo in the question, but the OA is A, which I don't think it's right. Attachment: 
r.JPG [ 5.67 KiB | Viewed 2261 times ]
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bigfernhead wrote: The figure above shows the present position on a radar screen of a sweeping beam that is rotating at a constant rate in a clockwise direction. In which of the four quadrants will the beam lie 30 seconds from now ? (1) In each 30-second period, the beam sweeps through 3.690° (2) r = 40 Not sure if there's a typo in the question, but the OA is A, which I don't think it's right. Attachment: r.JPG IMO C should be the correct answer.
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I will go with C as well
Here is why
1 - Don't know beams current position - Insuff
2- Insuf
Together I know where currently the beam is and the rate
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HG wrote: I will go with C as well
Here is why
1 - Don't know beams current position - Insuff
2- Insuf
Together I know where currently the beam is and the rate You need not to have value of R, as question says its angular rotation which will be same irespective of value of r. Hence stem 1 is suff.
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I think its a typo error in answer A and it shuld b 360 degree which makes sense of the OA (A)
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Just after looking at the figure think that angle r is 2degrees and then think that angle r is say 10 degrees.
When you think that it is 2 degrees then after 30 seconds we the beam will in quadrant 2.
If angle r is 10degrees then after 30 seconds it will stay in quadrant 1.
All the books says that the figure are not drawn to scale in a DS question.
There is no way option A is suff.
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The present position of radar: 0 < r < 90 degrees
A: during 30 seconds the beam will sweep through 3690 degrees, i.e. 3600 + 90 degrees: it will make 10 complete turns + 90 more degrees. We will have 0+90 < r+90 < 90+90 => 90 < r+90 < 180, which tells us that the beam will be in the 2nd quadrant.
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I agree that A is not sufficient - you just don't know the current position of the beam.
C is sufficient.
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bigfernhead wrote: Can anyone provide further detail on why the OA is A? I believe there is type in the question. It should be 3690° instead of 3.690° In this case Answer will be A . 3690 --> 360*10 +90 --> It will be in the fourth quadrant.. We don't require R value.
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Re: Radar.jpg 9. The figure above shows the present position on [#permalink]
14 Feb 2013, 12:24
The answer has to be C ... we cannot assume the initial position of r ..
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Re: Radar.jpg 9. The figure above shows the present position on [#permalink]
14 Feb 2013, 12:50
Hello Friends, just read in OG quant 2nd edition that The position of points, angles, regions, etc., exist in the order shown.so if the given figure showing the present position of radar in the middle of first quadrant, we can assume so and can go with choice A
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Re: Radar.jpg 9. The figure above shows the present position on
[#permalink]
14 Feb 2013, 12:50
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