Question

Find the value of a, b, c , d in the following equations?

  a  +  b  =  8
  +     +
  c  +  d  =  8
  =     =
 13     8

Answer 1

This question does not has a solution.
Horizontally: a + b = 8 and c + d = 8, thus a + b + c + d = 8 + 8 = 16
Vertically: a + c = 13 and b + d = 8, thus a + b + c + d = 13 + 8 = 21.
Therefore the problem is unsolvable.