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A certain marathon had 20,000 entrants, 52% of which were female and 3
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26 Jan 2017, 09:28
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Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
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26 Jan 2017, 10:32
ans B 720
amatuer runners = 40% of 20000 = 8000 8000 minus the female amtuer runner will givve the answer



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Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
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26 Jan 2017, 11:06
Bunuel wrote: A certain marathon had 20,000 entrants, 52% of which were female and 30% of these female entrants were professional runners. If 60% of the entrants were professional, how many of the runners in the marathon were amateur male runners?
A. 72 B. 720 C. 3,120 D. 8,000 E. 8,880 No. of females = 52% of 20000 = 10400 Professional females = 30% of 10400 = 3120 Total professional(M+F) = 60% of 20000 =12000 thus male professional = total professional  female professional = 120003120 = 8880 amateur males = Total runners (total females + professional male) = 20000 (10400+8880) =720 Ans B



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Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
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14 Aug 2017, 11:16
Amateur Professional Total Male 720(96008880) 8880(120003120) 9600(2000010400) Female 3120(30%*10400) 10400(52%*20000) Total 12000(60%20000) 20000(given) First calculate 52% then calculate 30% then calculate 60% then subtract 20000 10400 and also 120003120 then finally subtract 9600720
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A certain marathon had 20,000 entrants, 52% of which were female and 3
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25 Aug 2017, 22:53
Bunuel wrote: A certain marathon had 20,000 entrants, 52% of which were female and 30% of these female entrants were professional runners. If 60% of the entrants were professional, how many of the runners in the marathon were amateur male runners?
A. 72 B. 720 C. 3,120 D. 8,000 E. 8,880 the answer is in attached image. calculated through the easiest possible method! hope it helps!
Also, lemme know if any explanation is required!
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solution.jpg [ 75.9 KiB  Viewed 928 times ]



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Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
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25 Aug 2017, 23:16
Bunuel wrote: A certain marathon had 20,000 entrants, 52% of which were female and 30% of these female entrants were professional runners. If 60% of the entrants were professional, how many of the runners in the marathon were amateur male runners?
A. 72 B. 720 C. 3,120 D. 8,000 E. 8,880 Another approach  Draw a Tree Structure for these kind of questions As is clear from the tree structure below  No of amateur males \(= 0.036*20000 = 720\) Option B
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File comment: Tree Structure
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Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
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07 Sep 2017, 20:16
We can use 2X2 Matrix to solve questions of these types
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Screen Shot 20170908 at 9.45.22 AM.png [ 26.96 KiB  Viewed 757 times ]



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Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
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19 Jul 2018, 11:44
Bunuel wrote: A certain marathon had 20,000 entrants, 52% of which were female and 30% of these female entrants were professional runners. If 60% of the entrants were professional, how many of the runners in the marathon were amateur male runners?
A. 72 B. 720 C. 3,120 D. 8,000 E. 8,880 Since 52% of the 20,000 entrants were female, 0.52 x 20,000 = 10,400 were female and hence 20,000  10,400 = 9,600 were male. Since 30% of the female entrants were professional runners, 0.3 x 10,400 = 3,120 females were professional runners and hence 10,400  3,120 = 7,280 females were amateur runners. Since 60% of the entrants were professional runners, 0.6 x 20,000 = 12,000 were professional runners and hence 20,000  12,000 = 8,000 were amateur runners. Since there are 7,280 female amateur runners, there are 8,000  7,280 = 720 male amateur runners. Answer: B
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