The integers from 1 to 49 are written in a 7×7 table, such that for any k∈{1,2,…,7} the product of the numbers in the k-th row equals the product of the numbers in the (8−k)-th row. Prove that there exists a row such that the sum of the numbers written on it is a prime number. Give an example of such a table. Cristi Săvescu