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One-fifth of the light switches produced by a cer¬tain factory are defective. Four-fifths of the defective switches are rejected and 1/20 th of the nondefective switches are rejected by mistake. If all the switches not rejected are sold, what percent of the switches sold by the factory are defective? (A) 4% (B) 5% (C) 6.25% (D) 11% (E) 16%
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Last edited by vannu on 14 Aug 2009, 09:46, edited 1 time in total.
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vannu wrote: One-fifth of the light switches produced by a cer¬tain factory are defective. Four-fifths of the defective switches are rejected and of the nondefective switches are rejected by mistake. If all the switches not rejected are sold, what percent of the switches sold by the factory are defective? (A) 4% (B) 5% (C) 6.25% (D) 11% (E) 16% I guess there is somethings missing here "Four-fifths of the defective switches are rejected and of the nondefective switches are rejected by mistake"
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vannu wrote: One-fifth of the light switches produced by a cer¬tain factory are defective. Four-fifths of the defective switches are rejected and of the nondefective switches are rejected by mistake. If all the switches not rejected are sold, what percent of the switches sold by the factory are defective? (A) 4% (B) 5% (C) 6.25% (D) 11% (E) 16% There seems to be some missing data in the highlighted part.
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i too got confused by the highlighted sentence.. is the prblm statemnt clear..
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I edited the question. Sorry for the inconvenience.
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vannu wrote: One-fifth of the light switches produced by a cer¬tain factory are defective. Four-fifths of the defective switches are rejected and 1/20 th of the nondefective switches are rejected by mistake. If all the switches not rejected are sold, what percent of the switches sold by the factory are defective? (A) 4% (B) 5% (C) 6.25% (D) 11% (E) 16% assume 1000 produced 200 defective , 160 defective and rejected, 40 nondefective rejected by mistake 40 defective and not rejected , 760 non defective and not rejected, total non rejected and sold = 800 percent of the switches sold by the factory are defective = 40/800*100 = 5%
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vannu wrote: One-fifth of the light switches produced by a cer¬tain factory are defective. Four-fifths of the defective switches are rejected and 1/20 th of the nondefective switches are rejected by mistake. If all the switches not rejected are sold, what percent of the switches sold by the factory are defective? (A) 4% (B) 5% (C) 6.25% (D) 11% (E) 16% Assume x as the number of switches and that x =100 Defective Switches = 1/5 * 100 = 20 Defective Switches that are rejected = 4/5 * 20 = 16 Defective Switches that are sold = 20 - 16 = 4 Non-defective Switches = 100 - 20 = 80 Non-defective Switches mistakenly rejected = 80*1/20 = 4 Non-defective Switches that are sold = 80 - 4 = 76 Total sold in the market = 76 + 4 = 80 % of defective = (4/80)*100 = 5% ANS: B
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This may be a very stupid question but please help me understand how did we derive at(4/80)*100 ??
Is there a formula for this??
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vannu wrote: One-fifth of the light switches produced by a certain factory are defective. Four-fifths of the defective switches are rejected and 1/20 th of the nondefective switches are rejected by mistake. If all the switches not rejected are sold, what percent of the switches sold by the factory are defective? (A) 4% (B) 5% (C) 6.25% (D) 11% (E) 16%
| Rejected | Not Rejected | |
| Defective | a | b | c |
| Not Defective | d | e | f |
| g | h | i |
Fill in this order: i=100 1/5 of total= Defective i.e. 1/5*100=20 Defective. c=20 Not Defective=100-20=80, f=80 4/5 of Defective=Rejected= 4/5*20=16. a=16 b=c-a i.e. b=20-16=4 1/20 th of the nondefective switches are rejected 1/20*80=4. d=4 g=a+d=16+4=20 h=i-g=100-20=80 Defective+Not Rejected=b=4 Total Not Rejected=h=80 %=4/80*100=5
| Rejected | Not Rejected | |
| Defective | 16 | 4 | 20 |
| Not Defective | 4 | e | 80 |
| 20 | 80 | 100 |
Ans: "B"
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thanks fluke, dis approach did help me understand the question better...
this was my first post..i have couple of more questions wherein i need your advice..pls suggest if i need to open up a new topic for every question or can i post my queries alongside the existing post..like what i did in this one..
thanks again!!
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DeeptiM wrote: thanks fluke, dis approach did help me understand the question better...
this was my first post..i have couple of more questions wherein i need your advice..pls suggest if i need to open up a new topic for every question or can i post my queries alongside the existing post..like what i did in this one..
thanks again!! Please reply to the existing post. If the question is not discussed before, create a new thread.
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