Party A and Party B need to be on duty for four days from Monday to Thursday, two days each. If the specific arrangement is decided by drawing lots, there will be no probability that the same person w

Party A and Party B need to be on duty for four days from Monday to Thursday, two days each. If the specific arrangement is decided by drawing lots, there will be no probability that the same person will be on duty continuously. Party A and Party B are required to be on duty from Monday to Thursday for four days, two days each.

Then all the permutations are: a, b, b; Party A and Party B; Party A and Party B; B，B，A； B, A, B, A; Party B, Party A, Party B, ***6 situations,

If the same person is not on duty continuously, there are Party A and Party B; Two schemes, B, A, B, A and * * *,

So the probability that the same person is not on duty continuously is 13.

So the answer is: 13.