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N is an integers and N>2 at most how many integers among N+2,N+4,N+5,N+6 and N+7 are prime integers?
a) 1 ,b)3 ,c)2, d)4
Read Solution (Total 8)
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- 2....
start with 3...we got 5,6,7,8,9
we gust got 2 prime no among them.
and it is true for any no. of n. - 12 years agoHelpfull: Yes(34) No(3)
- Ans. (c) 2
For N=3 we have - 5,7,8,9,10 so 2 prime
For N=4 we have - 6,8,9,10,11 so 1 prime
For N=5 we have - 7,9,10,11,12 so 2 prime
For N=6 we have - 8,10,11,12,13 so 2 prime
& so on....
So max no of Primes are 2
- 12 years agoHelpfull: Yes(17) No(1)
- 2....
start with 3...we got 5,7,8,9,10
we gust got 2 prime no among them.
and it is true for any no. of n.
Here 5 and 7 prime integers. - 12 years agoHelpfull: Yes(13) No(0)
- every prime no. follows the logic
6N+1 or 6N-1.
but this doesnt mean every no which follows this logic is prime.
except 2,all prime no.s are odd.
now,
since N is an integer,so 6N will always be even. to make it odd we have to add an odd no to 6N.
in our question we have only to set which can make odd(N+5 and N+7). so we can have max of two prime no.
ans=c - 12 years agoHelpfull: Yes(7) No(0)
- c)2..if let n=3
- 12 years agoHelpfull: Yes(3) No(8)
- if we solve this question by putting n as 3,4,5,6 n so on
we got max 2 prime no each time as pattern flow with numbers
if we put number from 3 we get
For N=3 we have - 5,7,8,9,10 so 2 prime
For N=4 we have - 6,8,9,10,11 so 1 prime
For N=5 we have - 7,9,10,11,12 so 2 prime
For N=6 we have - 8,10,11,12,13 so 2 prime
& so on..
so 2 is common prime number,
That why answer is 2 - 9 years agoHelpfull: Yes(1) No(0)
- ans: 4
5, 7, 11, 13
- 9 years agoHelpfull: Yes(0) No(3)
- just consider n=19
out of 20,21,22,23,24,25,26
only 23 is prime - 8 years agoHelpfull: Yes(0) No(0)
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