Question

[vu gia huy]

Find the prime number p such that p+2 P=94 and  are also prime numbers.h 

nhanh len minh dang can gap

ko can giai

Answer 1

[Đào Trọng Luân]

If p = 2 => p + 2 and p + 94 \(⋮\)2 [eliminate]

If p = 3 => p + 2 = 5 and p + 94 = 97 [satisfactorily]

If p > 3 => p = 3k + 1 or p = 3k + 2

** if p = 3k + 1 => p + 2 \(⋮\)3 [eliminate]

** if p = 3k + 2 => p + 94 \(⋮\)3 [eliminate]

Conclude: p = 3