Question 1184589
Best to do this on graph paper to get your mind going. Below is used to find out which activity going down vertically belongs with the location horizontally. Xs are where they dont go by eliminating them from the word problem. 
[.][A][C][P][S]
[c][x][x][*][x]
[s][_][_][x][_]
[o][_][_][x][_]
[b][_][_][x][_]

Coin collectors met in Philadelphia. There is not enough information to find out the other 3. You are missing alot of info. Esp since july and august mean nothing without any information that attributes to months for either the convention order or topic. 
The question doesnt indicate that its 1 month per con or multiple cons in a month. 

Make sure you copy the ENTIRE problem before submitting.