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Re M2010
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16 Sep 2014, 01:08



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Re M2010
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14 Jun 2016, 09:12
I don't agree with the explanation. If the Number is 30 and you substract it by 9 you get 21 and hence the tens digit is 2; Similarly the number 29  9 =20 and the tens digit is 2 again



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parmarankita26 wrote: I don't agree with the explanation. If the Number is 30 and you substract it by 9 you get 21 and hence the tens digit is 2; Similarly the number 29  9 =20 and the tens digit is 2 again Hi, this is exactly the reason why statement II is not sufficient alone  you should take N as initial value 30 and 29 and not the answer N9.. The explanation also is the same so why you don't agree to it?
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Re: M2010
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14 Jun 2016, 09:17



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Re: M2010
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26 Sep 2017, 05:56
Bunuel could you solve this question mathematically



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Re: M2010
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26 Sep 2017, 11:29
If NN is a twodigit positive integer, what is the value of its tens digit?
(1) 2N is a twodigit integer whose tens digit is 7
(2) The tens digit of (N−9)(N−9) is 2
Sol A As given in option A ten digit is 7,this is only possible when we have 3 as Unit digit if it is able to create one carry to ten digit(30*2=60 34*2=6_ but from 35*2 to 39*2= 7_ With this logic ,we are left with options 35,36,37,38,39 only. Hence,for all options,Ten digit is3Sufficient B Subtract all above choices with 9 and you will get two options as: 2_ or 30 . Insufficient Hence, Option A



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Re: M2010
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26 Sep 2017, 19:03
2N can be any of the five numbers: 70, 72, 74, 76, 78, since the tens digit is 7 and the number is an even number (multiplied by 2). In any of these cases the tens digit of N is 3. Hence, Statement (1) by itself is sufficient.
Now from statement 2:
Consider N=30, the tens digit is 3 and for N=29 the tens digit is is 2. Hence, Insufficient
Answer: A










