Three non negative numbers A, B and C are such that the mean is X and the median is 7. If X is 12 more than the smallest number and 17 less than the biggest number. Find the value of A + B + C.
If a, b, c and d are distinct pairwise co-prime positive integers such that a^2 + b^2 = c^2 + d^2, find the lowest possible value of a + b + c + d?
