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Re: If n is a three-digit prime number and j is an integer, which of the
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13 Jun 2021, 02:04
n – 5j = k
=> n = 5j + k
and we know that n is a three-digit prime number and j is an integer
Now, if k is a number such that k and 5j have any factor apart from 1 common then it is easy to prove that n will not be prime in that case
If we have take option number E, k = 5 then we have
n = 5j + 5 = 5 *(j + 1)
Now, n becomes a multiple of 5 and j+1 which is NOT possible as n is a prime number
So, k cannot be 5
So, answer will be E
Hope it helps!