In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?
A, B, C, D and E are standing in a line facing North. E is standing 40 metres left to B. A is standing 20 metres left to C. D is standing 20 metres right to E and 50 metres right to C. Where is B standing from D?