Is the positive integer n an odd integer?
(1) n+4 is a prime number
(2) n+3 is not a prime number.
Answer: A
please help.
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rdchandvadkar
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thephoenix
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s1) n+4=prime no and nis +ve int-----> n is odd
bcoz the only prime no which is even is 2 and rest all are odd
hence n can be 3,7,13,19,27....all odd value only give a prime no.
suff
s2)
n+3 is a prime no.
if n=6(even)
n+3=9 not a prime no
if n=3 (odd)
n+3=6 not a prime no
hence insuff
bcoz the only prime no which is even is 2 and rest all are odd
hence n can be 3,7,13,19,27....all odd value only give a prime no.
suff
s2)
n+3 is a prime no.
if n=6(even)
n+3=9 not a prime no
if n=3 (odd)
n+3=6 not a prime no
hence insuff
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ajith
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1. All the prime numbers except 2 are odd. In this case n is not equal to 2 anyway, sufficient to conclude that n is oddrdchandvadkar wrote:Is the positive integer n an odd integer?
(1) n+4 is a prime number
(2) n+3 is not a prime number.
Answer: A
please help.
2. n+3 is not a prime number is not sufficient (7+3, 6+3 both are not prime) to decide whether n is prime or not
Hence A
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rdchandvadkar
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harsh.champ
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Important pt. :-All the prime no.s are odd except 2.rdchandvadkar wrote:Is the positive integer n an odd integer?
(1) n+4 is a prime number
(2) n+3 is not a prime number.
Answer: A
please help.
1:- n+4=prime ,hence n = odd - even = odd Sufficient.
2:- n+3=not prime , but it can be 9 as well as 8 .Hence insufficient.
The OA should be A.
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