# Day 23: Last Minute Christmas Rush!

Probability Level 4

A disorganised mathematician is doing all his Christmas preparation in two days to make a party for his friends. He, being systematic, has made a list of seven activities: $A,B,C,D,E,F,$ and $G$, to do (one at a time). However:

1. $A$ (buying Christmas food and presents) must be done before $B$ (preparing food).
2. $E$ (making math problems for his friends) must be done as one of the first four activities (because he thinks better in the morning).

For example, one valid way is $ABCEDFG$. In total, how many ways are there for him to do the activities?

This problem is part of the set Advent Calendar 2014.

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