Question 513810

FIND AL NUMBERS LESS THAN 50THAT ARE PRIMES AND HAVE A REMAINDER OF 3 WHEN THEY ARE DIVIDED BY 7.


Multiply all numbers, from 1 to 6, by 7, and than add 3 to see if the result is a prime number. 


N.B. Multiplying 7 by 7, and adding 3 would yield 52 (7*7 + 3), which would be too large


_7 * 1 = 7 + 3 = 10 (NOT PRIME)
7 * 2 = 14 + 3 = 17 (PRIME)
7 * 3 = 21 + 3 = 24 (NOT PRIME)
7 * 4 = 28 + 3 = 31 (PRIME)
7 * 5 = 35 + 3 = 38 (NOT PRIME)
7 * 6 = 42 + 3 = 45 (NOT PRIME)
7 * 7 = 49 + 3 = 52 (NOT PRIME, and as stated above, 52 > 50)


Therefore, the numbers being sought are {{{highlight_green(17)}}} and {{{highlight_green(31)}}}


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