Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 49430

A certain marathon had 20,000 entrants, 52% of which were female and 3
[#permalink]
Show Tags
26 Jan 2017, 10:28
Question Stats:
64% (01:51) correct 36% (01:52) wrong based on 154 sessions
HideShow timer Statistics



Director
Joined: 21 Mar 2016
Posts: 531

Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
[#permalink]
Show Tags
26 Jan 2017, 11:32
ans B 720
amatuer runners = 40% of 20000 = 8000 8000 minus the female amtuer runner will givve the answer



Director
Joined: 05 Mar 2015
Posts: 985

Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
[#permalink]
Show Tags
26 Jan 2017, 12:06
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



Manager
Status: Math Tutor
Joined: 12 Aug 2017
Posts: 74
WE: Education (Education)

Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
[#permalink]
Show Tags
14 Aug 2017, 12:16
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
_________________
Abhishek Parikh Math Tutor Whatsapp +919983944321 Mobile +971568653827 Website: http://www.holamaven.com



Intern
Joined: 16 Feb 2017
Posts: 22

A certain marathon had 20,000 entrants, 52% of which were female and 3
[#permalink]
Show Tags
25 Aug 2017, 23:53
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!
Attachments
solution.jpg [ 75.9 KiB  Viewed 877 times ]



PS Forum Moderator
Joined: 25 Feb 2013
Posts: 1217
Location: India
GPA: 3.82

Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
[#permalink]
Show Tags
26 Aug 2017, 00:16
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
Attachments
File comment: Tree Structure
Tree structure.jpg [ 42.65 KiB  Viewed 866 times ]



Manager
Joined: 04 May 2014
Posts: 161
Location: India
WE: Sales (Mutual Funds and Brokerage)

Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
[#permalink]
Show Tags
07 Sep 2017, 21:16
We can use 2X2 Matrix to solve questions of these types
Attachments
Screen Shot 20170908 at 9.45.22 AM.png [ 26.96 KiB  Viewed 706 times ]



Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 3528
Location: United States (CA)

Re: A certain marathon had 20,000 entrants, 52% of which were female and 3
[#permalink]
Show Tags
19 Jul 2018, 12:44
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
_________________
Scott WoodburyStewart
Founder and CEO
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions




Re: A certain marathon had 20,000 entrants, 52% of which were female and 3 &nbs
[#permalink]
19 Jul 2018, 12:44






