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?
A, B and C can complete a task together in 10 days. A and B would need 12 days if only the two of them worked, while B and C would take 20 days if only the two of them worked. If B worked alone, how many days would she take to complete the task?