Solve this number puzzle and find out the possible value for a,b,c and d.
A is 4 d is 20 d is 2
A 4 b 2 c 1 Md 3
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?
Solve this puzzle.
