# ISI 2012 ME - I Answer Key

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## Re: ISI 2012 ME - I Answer Key

 Q 22 ...help needed MA Economics DSE 2014-16
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## Re: ISI 2012 ME - I Answer Key

 In reply to this post by lovekesh can some one please explain question no.-3
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## Re: ISI 2012 ME - I Answer Key

 In reply to this post by lovekesh take x>=0, which gives f(x)= x/(1+x), Now differentiate f(x) wrt x it gives f'(x)=[1/(1+x)]-[x/(1+x)^2]=1/(1+x)^2>=0 for all x>0, so the function is monotone increasing for this domain of x hence ans is option a.  "I don't ride side-saddle. I'm as straight as a submarine"
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## Re: ISI 2012 ME - I Answer Key

 In reply to this post by manisha For Q3, elements of A1 can be derived by putting n=1 and k=1,2,3....in A(n)=(n+1)*k, thus A1={(1+1)*1, (1+1)*2, (1+1)*3,(1+1)*4.......}={2,4,6,8,10,12,14,16,18...}, similarly A2= {3,6,9,12,15,18.......}, Thus A1 intersection A2= {6,12,18,24,........}= A5, verify putting n=5 and respective values of k with A5.  "I don't ride side-saddle. I'm as straight as a submarine"
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## Re: ISI 2012 ME - I Answer Key

 In reply to this post by SoniaKapoor for Q23 use integration(logx)= log mod(x), remember its not log x which implies log mod(-4)=log 4 and similarly log mod (-1)= log 1, use this after integrating (1/x) and u will get answer as -log (4), so option d is the answer.  "I don't ride side-saddle. I'm as straight as a submarine"
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## Re: ISI 2012 ME - I Answer Key

 thanku
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## Re: ISI 2012 ME - I Answer Key

 In reply to this post by Granpa Simpson pls explain ques 11
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 In reply to this post by Amit Goyal @neha Let sides of rect be x and y resp area=l*b =x(l-x) =lx-x^2 diff wrt x l-2x=0 x=l/2 second order condn also satisfied thus line should be divided in 1:1
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## Re: ISI 2012 ME - I Answer Key

 thanks ron pls explain ques 7
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## Re: ISI 2012 ME - I Answer Key

 can someone explain Q.23 and Q.25???
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## Re: ISI 2012 ME - I Answer Key

 Hi All, Can some one please help me with : Q 8 (unable to understand the question part) a link to understand this is much appreciated. Q 12 (I got the correct answer by random substitution, but please explain the methodology) Q 18 Q 24 Q 30 (I feel it is C and not A )
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## Re: ISI 2012 ME - I Answer Key

 Q 24. Begin by determining probability that none of the plugs pulled are faulty. This is : (4 C 2)/ 6 C 2. We get 6/15. The probability that atleast one is faulty therefore is simply 1 - (none being faulty). Thus, 1 - 6/15. Ans. 9/15 Q 30. I suspect its C as well, f(x) seems to increase for every value of x.
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## Re: ISI 2012 ME - I Answer Key

 No. of ways = C(6,3)*C(5,2)  -  C(4,1)*C(5,2)                   =160