Six lectures A, B, C, D, E and F are to be organised in a spam of seven days -- from Sunday to Saturday, only one lecture on each day in accordance with the following :
- A should not be organised on Thursday.
- C should be organised immediately after F.
- There should be a gap of two days between E and D.
- One day there will be no lecture (Friday is not that day), just before that day D will be organised.
- B should be organised on Tuesday and should not be followed by D.
How many lectures are organised between C and D ?
B is organised on Tuesday. Now, D is followed by the day with nno lecture. D cannot be organised on Friday because then E will be on Tuesday (there is a gap of two days between D and E). It cannot be organised on Thursday (because then, there will be no lecture Friday). B cannot be followed by D. So, D will be organised on Sunday and E on Wednesday. No lecture will be organised on Monday. A cannot be organised on Thursday. So, A will be organised on Saturday. F and C will be organised on Thursday and Friday respectively.
So the correct order is :
So, Three lectures are organised between C and D -- B, E and F.