Elitmus
Exam
Logical Reasoning
Decision Making and Problem Solving
If N is a positive integer than the no. of factors of 12N are?
(i)if N is a prime number
(ii)if N is an odd number
(a) (b) (c) (d)
Read Solution (Total 14)
-
- 12N = 2*2*3*N=2^2 * 3^1 * N-------------------------------- equation(1)
Now check one by one both statmt
if N = prime NO(2,3,5,7----)
if N=2 then Number of factor 12*2=2^3*3^1=(3+1)(1+1)= 8
if N=3 then 12*3= 2^2*3^2=(2+1)(2+1)= 9
therefore No of factor change by changing prime no.
similarly No of factor change by changing odd no
therefore both not give accurate ans
option d is correct - 9 years agoHelpfull: Yes(20) No(6)
- i think statement one is sufficient
- 9 years agoHelpfull: Yes(9) No(7)
- Any of the statement is sufficient to ans the question because i think when we put any prime no or any odd number ,it gives a different output and offcorse gives the factor of that no,so any of the stmt is suffficient to give the ans and here qstn is just asking the factor of 12N ,which ever we put ,we get a result .so any of the stsm is sufficient .
- 9 years agoHelpfull: Yes(5) No(3)
- BINESH, I think its all about whether we could find the result using the statement(s).
If he had declared that 12N has 12 factors, then what you have said might be correct.
But here the question is "can we find the factors of 12N?"
So, I think we could find the result even if N is even odd prime etc.
What is the value of N matters next.
I did the mistake yesterday but later I realized after the exam :-( - 9 years agoHelpfull: Yes(3) No(3)
- we need to calculate the no of factors of no ie. 12N
(i) If a no is prime factors will definitely have 4 factors ie. 1,2,3,N (since N is a prime no and cannot be factorise further)
(II) If no is an odd number can be factorise ie. 35 has factors 5,7.
so this condition is not sufficient
(a) will be the ans - 9 years agoHelpfull: Yes(2) No(0)
- Factors for any natural number can be found dividing it into prime factors.
So N can be prime number or odd number - 9 years agoHelpfull: Yes(1) No(3)
- BOTH THE STATEMENT ARE INSUFFICIENT. CAUSE NO STATEMENT TELLS ABOUT THE UNIQUE VALUE OF "N".
- 9 years agoHelpfull: Yes(1) No(1)
- 12N=(2^2)*3*(N)
Taking 1st option if N is prime no.
So N=N*1
So the no of factors = (2+1)(1+1)(1+1)=12
So (i) satisfies
Now taking 2,
We cant get unique solution
So only (i) is sufficient. - 9 years agoHelpfull: Yes(1) No(1)
- what was the corect ans sidhartha@
- 9 years agoHelpfull: Yes(0) No(1)
- Shaik Umme rumana....... Either of the statements is ok to answer
- 9 years agoHelpfull: Yes(0) No(7)
- Any body appearing for elitmus exam on 19th july in pune , please share me the exam location
- 9 years agoHelpfull: Yes(0) No(0)
- Ans:12
Sol: 12N
where N is odd prime no {3,5,7,11,13...................97}
factors are 2^2*3^1*N^1
where formula is p^a*q^b*r^c then no of factor is (a+1)*(b+1)*(c+1)
similarly
(2+1)*(1+1)*(1+1)=3*2*2=12 (except at N=3)
for N=3 then
factor is 12*3=2^2*3^2=(2+1)*(2+1)=9 - 9 years agoHelpfull: Yes(0) No(0)
- Ans is Statement a is sufficient becoz prime number has only 2 factors including 1 . 12 has 6 factors . So total it will be 7 because 1 is already included in 12
- 8 years agoHelpfull: Yes(0) No(1)
- Both the statement are insufficient .
If N is prime then......
For N=2,
For 12*2= 2*2*2*3
Noof factor = 4*2=8( by no of factor concept)
For N=3,
Similarly as above.....12*3=2*2*3*3
No of factor = 3*3 = 9
For N other 2 or 3 ,no of factor = 12
12*N= 2*2*3*N
No of factor = 3*2*2 =12
If N is odd
The we can't say how many factors are there..it depends on the value of N. - 8 years agoHelpfull: Yes(0) No(0)
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