@Mr. Sawhney: I wrote the earlier email to provide a method of solving the problem at hand, not to spoon feed with exact numbers. If I write 15000 instead of 150000, it should not be so difficult to find out the solution. Secondly, look at the below calculations to understand how the method of multiplying the given number (150000) twice to get the population 2 years ago is incorrect.
Method 1 - Suggested by Mr. Kanchwala: Current Population (given) = 1,50,000 Population 2 years back = 1,36,054 (calculated as 1,50,000 / 1.1025) Population 1 year back = 1,42,857 (calculated as 1,36,054 * 1.05) Current Population = 1,50,000 (calculated as 1,42,857 * 1.05) Method 2 - Suggested by Mr. Sharma: Current Population (given) = 1,50,000 Population 2 years back = 1,35,375 (calculated as 1,50,000 * 0.95 * 0.95) Population 1 year back = 1,42,144 (calculated as 1,35,375 * 1.05) Current Population = 1,49,251 (calculated as 1,42,144 * 1.05) Taking the calculated population 2 years back using the two methods, one should be able to get the current population as given in the problem. This does not happen in case of method 2 because 5% of 95 is not 5, it's 4.75. Population 2 years back would be calculated as 0.9025x (0.95 * 0.95). Population 1 year back would be 0.9025x + 0.045125x = 0.947625x and current population would be 0.947625x + 0.04738125x = 0.99500625x whereas it should be x. The logic is simple - If you want to add 5% then multiply by 1.05 and if you want to subtract 5% then divide by 1.05. Note that I am rounding off the numbers as population cannot be expressed as a decimal number, Best Regards, Zujar. An optimist laughs to forget and a pessimist forgets to laugh! -----Original Message----- From: AccessIndia [mailto:accessindia-boun...@accessindia.org.in] On Behalf Of Mohib Anwar Rafel Sent: Monday, June 24, 2013 10:21 PM To: accessindia@accessindia.org.in Subject: Re: [AI] help me in understanding the method for solving such type of mathematical problems Thank you all. On 6/24/13, Kartik Sawhney <sawhney.kar...@gmail.com> wrote: > Hi, > > Rather than trying to understand the terminology, one can simply > understand the implication and complete the problem easily. For > instance, it isn't vital to understand the word `union`, and simply > understanding what it implies (either....or....both) is sufficient. So > basically, one can adopt an approach similar to the one in set theory, > without delving into its details as such. This way, the problems can > be approached a lot more efficiently in my view. > > Best, > > On 6/24/13, Vedprakash <vedprakash.sha...@gmail.com> wrote: >> Yes, the set theory is easy but most of us have gone through mathes >> up to tenth level. >> That is why, the terms like a union b, or complementary etc., are new >> to such aspirants. >> ----- Original Message ----- >> From: "Kartik Sawhney" <sawhney.kar...@gmail.com> >> To: <accessindia@accessindia.org.in> >> Sent: Monday, June 24, 2013 11:09 AM >> Subject: Re: [AI] help me in understanding the method for solving >> such type >> >> of mathematical problems >> >> >>> Hi, >>> >>> The solution as suggested by Mr. Sharma to 1B, is in fact, correct. >>> Accidently, Mr. Kanchwala has taken 150000 as 15000, resulting in >>> the anomaly. >>> >>> Further, the solution to the second question as suggested is very >>> complecated. An easy way of approaching this is by employing set >>> theory. >>> >>> Let h be the set of students who failed in Hindi, and E be the set >>> of students who failed in English Let the total No. of students in >>> the class=100 Now, we have: >>> No. of elements in H=35 >>> No. of elements in E=45 >>> Further, No. of elements in E intersection H=20 Further, we know: >>> E u H=No. of elements in e+No. of elements in H-No. of elements in e >>> intersection h Where u is union (You can learn this formula for this >>> type of problems, it will prove >>> handy) >>> Therefore, in this case: >>> e u h=35+45-20=60 >>> Now, 60 students failed in either English or Hindi or both. >>> Therefore, students who did not fail in either of the subjects >>> (rather who passed in both the subjects)=100-60=40 >>> >>> Best, >>> >>> >>> On 6/23/13, Zujar Shabbir Kanchwala <zujarbri...@gmail.com> wrote: >>>> Pardon me for addressing this post to the list. >>>> >>>> I see that the solution suggested for question # 1b by Mr. S P >>>> Sharma isn't correct and it needs be known to fellow list members >>>> so that they can correct themselves. If one multiplies 15000 by 95% >>>> twice to get the population 2 years back then the answer is 135375. >>>> This answer is incorrect, the correct answer is 13605. >>>> >>>> Here's the explanation: >>>> >>>> Let x be the population 2 years back. >>>> >>>> 1 year back the population would be: >>>> x + 0.05x >>>> =1.05x >>>> >>>> Current year the population would be: >>>> 1.05x + (0.05 * 1.05)x >>>> =1.05x + 0.0525x >>>> =1.1025x >>>> >>>> Given that current year the population is 15000. >>>> So, 1.1025x = 15000 >>>> Therefore, x = 15000 / 1.1025 >>>> =13605.44 rounded off to 13605. >>>> >>>> Note that 5% of 100 is 5 but 5% of 95 is 4.75 not 5. So, if the >>>> population >>>> 1 >>>> year back is 95 then current year it would be 95+4.75=99.75 and not >>>> 100. >>>> >>>> The compound interest method suggested by Mr. Vedprakash fits in >>>> best for such problems, it's shorter than the above method. I >>>> mentioned the above method to explain how it works. >>>> >>>> Hope this is clear... >>>> >>>> Best Regards, >>>> Zujar. >>>> >>>> An optimist laughs to forget and a pessimist forgets to laugh! >>>> >>>> -----Original Message----- >>>> From: AccessIndia [mailto:accessindia-boun...@accessindia.org.in] >>>> On Behalf Of Vedprakash >>>> Sent: Sunday, June 23, 2013 11:25 AM >>>> To: accessindia@accessindia.org.in >>>> Subject: Re: [AI] help me in understanding the method for solving >>>> such type of mathematical problems >>>> >>>> Sorry for a wrong answer of the second question. sending the same >>>> again. >>>> 2. In a class 35% students failed in hindi, 45% failed in english >>>> subjects respectively. 20% students failed in both subjects, find >>>> out the percentage of the students who passed in both subjects. >>>> Total numbers of the students: = 100 Failed in Hindi = 35% Passed >>>> in Hindi: = 100 minus 35 = 65. >>>> Failed in English: = 45 >>>> passed in English = 100 minus 45 = 55. >>>> failed in both = 20. >>>> Passed in either Hindi or English = 100 minus 20 = 80. >>>> Passed in Both = >>>> A. Passed in either Hindi or English minus Passed in Hindi = 80 >>>> minus >>>> 65 >>>> >>>> = >>>> 15 Plus B. Passed in either Hindi or English minus Passed in >>>> English >>>> =80 minus 55 = 25 >>>> = A plus B >>>> =15 plus25 >>>> =40 Answer. >>>> >>>> >>>> ----- Original Message ----- >>>> From: "Mohib Anwar Rafel" <mohibra...@gmail.com> >>>> To: "accessindia" <accessindia@accessindia.org.in> >>>> Sent: Saturday, June 22, 2013 9:34 PM >>>> Subject: [AI] help me in understanding the method for solving such >>>> type of mathematical problems >>>> >>>> >>>>> Hi friends I am unable to understand the way to solve the >>>>> following problems, even I couldn't understand it by reading R. S. Agarwal book. >>>>> please guide me. >>>>> >>>>> 1. If the population of a town is 1,50,000 at present, it is >>>>> increasing at the rate of 5% per annum, >>>>> (a) what will be the population of the town after 2 years? >>>>> (b) what was the population of the town before 2 years? >>>>> >>>>> 2. In a class 35% students failed in hindi, 45% failed in english >>>>> subjects respectively. 20% students failed in both subjects, find >>>>> out the percentage of the students who passed in both subjects. >>>>> >>>>> -- >>>>> Mohib Anwar Rafel >>>>> M.Phil/Masters in International Law, Center for International >>>>> Legal Studies JNU. >>>>> Pursuing Masters of Law, at University of Delhi >>>>> >>>>> Phone: 09811767506, >>>>> 01127666896 >>>>> >>>>> Register at the dedicated AccessIndia list for discussing >>>>> accessibility of mobile phones / Tabs on: >>>>> http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia >>>>> _acc >>>>> essindia.org.in >>>>> >>>>> >>>>> Search for old postings at: >>>>> http://www.mail-archive.com/accessindia@accessindia.org.in/ >>>>> >>>>> To unsubscribe send a message to >>>>> accessindia-requ...@accessindia.org.in >>>>> with the subject unsubscribe. >>>>> >>>>> To change your subscription to digest mode or make any other >>>>> changes, please visit the list home page at >>>>> http://accessindia.org.in/mailman/listinfo/accessindia_accessindia >>>>> .org >>>>> .in >>>>> >>>>> >>>>> Disclaimer: >>>>> 1. Contents of the mails, factual, or otherwise, reflect the >>>>> thinking of the person sending the mail and AI in no way relates >>>>> itself to its veracity; >>>>> >>>>> 2. AI cannot be held liable for any commission/omission based on >>>>> the mails sent through this mailing list.. >>>> >>>> >>>> Register at the dedicated AccessIndia list for discussing >>>> accessibility of mobile phones / Tabs on: >>>> http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia_ >>>> accessind >>>> ia.org.in >>>> >>>> >>>> Search for old postings at: >>>> http://www.mail-archive.com/accessindia@accessindia.org.in/ >>>> >>>> To unsubscribe send a message to >>>> accessindia-requ...@accessindia.org.in >>>> with the subject unsubscribe. >>>> >>>> To change your subscription to digest mode or make any other >>>> changes, please visit the list home page at >>>> http://accessindia.org.in/mailman/listinfo/accessindia_accessindia. >>>> org.in >>>> >>>> >>>> Disclaimer: >>>> 1. Contents of the mails, factual, or otherwise, reflect the >>>> thinking of the person sending the mail and AI in no way relates >>>> itself to its veracity; >>>> >>>> 2. AI cannot be held liable for any commission/omission based on >>>> the mails sent through this mailing list.. >>>> >>>> >>>> Register at the dedicated AccessIndia list for discussing >>>> accessibility of mobile phones / Tabs on: >>>> http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia_ >>>> accessindia.org.in >>>> >>>> >>>> Search for old postings at: >>>> http://www.mail-archive.com/accessindia@accessindia.org.in/ >>>> >>>> To unsubscribe send a message to >>>> accessindia-requ...@accessindia.org.in >>>> with the subject unsubscribe. >>>> >>>> To change your subscription to digest mode or make any other >>>> changes, please visit the list home page at >>>> http://accessindia.org.in/mailman/listinfo/accessindia_accessindia. >>>> org.in >>>> >>>> >>>> Disclaimer: >>>> 1. Contents of the mails, factual, or otherwise, reflect the >>>> thinking of >>>> >>>> the >>>> person sending the mail and AI in no way relates itself to its >>>> veracity; >>>> >>>> 2. AI cannot be held liable for any commission/omission based on >>>> the mails sent through this mailing list.. >>>> >>> >>> >>> -- >>> -Kartik Sawhney, >>> Mob.: 91-9560953728 >>> Landline: 91-11-29811529 >>> E-mail ID: sawhney.kar...@gmail.com (all personal E-mails); >>> karti...@stanford.edu (all academic E-mails) >>> Skype: kartik.sawhney22 >>> >>> Register at the dedicated AccessIndia list for discussing accessibility >>> of >>> >>> mobile phones / Tabs on: >>> http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia_accessind ia.org.in >>> >>> >>> Search for old postings at: >>> http://www.mail-archive.com/accessindia@accessindia.org.in/ >>> >>> To unsubscribe send a message to >>> accessindia-requ...@accessindia.org.in >>> with the subject unsubscribe. >>> >>> To change your subscription to digest mode or make any other changes, >>> please visit the list home page at >>> http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in >>> >>> >>> Disclaimer: >>> 1. Contents of the mails, factual, or otherwise, reflect the thinking of >>> the person sending the mail and AI in no way relates itself to its >>> veracity; >>> >>> 2. AI cannot be held liable for any commission/omission based on the >>> mails >>> >>> sent through this mailing list.. >> >> >> Register at the dedicated AccessIndia list for discussing accessibility >> of >> mobile phones / Tabs on: >> http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia_accessind ia.org.in >> >> >> Search for old postings at: >> http://www.mail-archive.com/accessindia@accessindia.org.in/ >> >> To unsubscribe send a message to >> accessindia-requ...@accessindia.org.in >> with the subject unsubscribe. >> >> To change your subscription to digest mode or make any other changes, >> please >> visit the list home page at >> http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in >> >> >> Disclaimer: >> 1. Contents of the mails, factual, or otherwise, reflect the thinking of >> the >> person sending the mail and AI in no way relates itself to its veracity; >> >> 2. AI cannot be held liable for any commission/omission based on the >> mails >> sent through this mailing list.. >> > > > -- > -Kartik Sawhney, > Mob.: 91-9560953728 > Landline: 91-11-29811529 > E-mail ID: sawhney.kar...@gmail.com (all personal E-mails); > karti...@stanford.edu (all academic E-mails) > Skype: kartik.sawhney22 > > Register at the dedicated AccessIndia list for discussing accessibility of > mobile phones / Tabs on: > http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia_accessind ia.org.in > > > Search for old postings at: > http://www.mail-archive.com/accessindia@accessindia.org.in/ > > To unsubscribe send a message to > accessindia-requ...@accessindia.org.in > with the subject unsubscribe. > > To change your subscription to digest mode or make any other changes, please > visit the list home page at > http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in > > > Disclaimer: > 1. Contents of the mails, factual, or otherwise, reflect the thinking of the > person sending the mail and AI in no way relates itself to its veracity; > > 2. AI cannot be held liable for any commission/omission based on the mails > sent through this mailing list.. > -- Mohib Anwar Rafel M.Phil/Masters in International Law, Center for International Legal Studies JNU. Pursuing Masters of Law, at University of Delhi Phone: 09811767506, 01127666896 Register at the dedicated AccessIndia list for discussing accessibility of mobile phones / Tabs on: http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia_accessind ia.org.in Search for old postings at: http://www.mail-archive.com/accessindia@accessindia.org.in/ To unsubscribe send a message to accessindia-requ...@accessindia.org.in with the subject unsubscribe. To change your subscription to digest mode or make any other changes, please visit the list home page at http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in Disclaimer: 1. Contents of the mails, factual, or otherwise, reflect the thinking of the person sending the mail and AI in no way relates itself to its veracity; 2. AI cannot be held liable for any commission/omission based on the mails sent through this mailing list.. Register at the dedicated AccessIndia list for discussing accessibility of mobile phones / Tabs on: http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia_accessindia.org.in Search for old postings at: http://www.mail-archive.com/accessindia@accessindia.org.in/ To unsubscribe send a message to accessindia-requ...@accessindia.org.in with the subject unsubscribe. To change your subscription to digest mode or make any other changes, please visit the list home page at http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in Disclaimer: 1. Contents of the mails, factual, or otherwise, reflect the thinking of the person sending the mail and AI in no way relates itself to its veracity; 2. AI cannot be held liable for any commission/omission based on the mails sent through this mailing list..
