Elitmus
Exam
Numerical Ability
Data Interpretation
is X=(100-n /n) a prime no?
i) n>4
II) n^2=25
Read Solution (Total 7)
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- first go thrgh S->1 i.e n>4 if check for n=10 then X=(100-10)/10=9(not prime)
So,S->1 is insufficient
then Go for S->2
i.e n^2=20..>n=-5,5
put n=-5, X=(100-(-5))/-5=-21(not prime)
So,S->1 is also insufficient
if we consider both S-> 1 & 2 (i.e n>4 & n^2=25 then the value of n=5 by both Statement)
So, if n=5 then X=(100-5)/5=19(prime no)
hence, Statements I and II together are necessary to answer the question - 9 years agoHelpfull: Yes(39) No(2)
- Both statement are required to answer the question.
1. is insufficient because if we put n=5 ,then X=19 which is a prime but if we put n=10,X=9 which is a composite number.
2. alone is not sufficient as n can be either +5 or -5,,,,+5 gives us 19 which is prime and -5 gives us 21 which is composite.
1+2 : n=5 we can say because n>4+n=5^2,,,,,,therefore -5 is invalid and only +5 is left which is a prime.
Therefore Answer= 1+2 :)))))
- 9 years agoHelpfull: Yes(4) No(1)
- @ Neha hoe Opt 2 is alone possible
S-2....>n^2=25( here value of n=5,-5)
if u put n=-5 then u got X=-21((100-(-5))/-5)
so,-21 is not a prime no
- 9 years agoHelpfull: Yes(3) No(1)
- i think option 2 is directly giving us a prime no.. so no need of option a..
then answer should be a) this can be solve throungh one of the answer alone but cannot be answered by using other statements alone.. - 9 years agoHelpfull: Yes(1) No(5)
- both statements are necessary
- 9 years agoHelpfull: Yes(1) No(1)
- I and II both together necessary to answer the question
n^2=25
n=+5,-5
n=-5 does not give prime no.
so that we will go through n=5 it will give us prime no.
which satisfy both condition(i.e n>4) - 8 years agoHelpfull: Yes(1) No(0)
- II is sufficient only
- 4 years agoHelpfull: Yes(0) No(0)
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