If n is any prime number greater than 2, which of the following CANNOT be a prime number?

A. n-4

B. n-3

C. n-1

D. n+2

E. n+5

All primes greater than 2 are odd;

So, n-4 is odd and can be prime but take n=6 gives n-4=2 is prime

n-3 could be even ie prime

n-1 sameway as above is prime

n+2 is odd and can be prime as the case is in 41, 43 & 11, 13 etc

n+5 is always even for all odds greater than 2 and hence is the answer

_________________

Sandy

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