It would depend on what you want to do with those 47 PCs. Generally one port on those 24 port switches would connect to another network device (switch or router) to connect to the OTHER 24 port switch. Consequently you only have 23 usable ports on each switch. Most higher end 24 port switches ALSO have expansion capabilities for 1 to 4 additional ports of some kind. Those ports might be fiber, or 10GE or just more regular copper ports. BUT if you have 48 total ports on two switches you can only connect 46 PCs if you want all of the PCs to connect to each other.