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One-fifth of the light switches produced by a certain factor
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04 Feb 2020, 07:39
04 Feb 2020, 07:39
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Question Stats:
25% (01:37) correct
75% (01:49) wrong based on 8 sessions
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One-fifth of the light switches produced by a certain factory are defective. Four-fifths of the defective switches are rejected and 1/20 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%
(A) 4%
(B) 5%
(C) 6.25%
(D) 11%
(E) 16%
Re: One-fifth of the light switches produced by a certain factor
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04 Feb 2020, 10:26
04 Feb 2020, 10:26
1
Expert Reply
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%
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%
Re: One-fifth of the light switches produced by a certain factor
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05 Feb 2020, 07:54
05 Feb 2020, 07:54
1
Asif123 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 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%
(A) 4%
(B) 5%
(C) 6.25%
(D) 11%
(E) 16%
I find it helpful to draw trees for such types of questions.
Lets assume that there are 100 switches in total than the tree looks like the following:
-----------------------------------------------------------\(\)----------- 4/5 of total rejected = 16 rejected
100 total---------- 1/5 of total is defective = 20 defective
---------------------------------------------------------------------- 1/5 of defective is sold = 4 sold
---------------------------------------------------------------------- 1/20 rejected by mistake = 4 rejected
100 total------------4/5 of total is not defective = 80
---------------------------------------------------------------------- 76 sold
Total 76+4= 80 switches is sold, out of which 4 is defective which is 4/80 = 5%.
