Edge Extenders extend wifi coverage up to 10,000 sqft per unit. However, thick walls can limit range. For hotels or to cover a multifamily building with wifi you will want to consider an Edge Extender in each room.
There is no limit to how many Edge Extenders you can connect. However all Edge Extenders do require power and must be hardwired to one-another via ethernet or through a switch*.
*A network switch is networking hardware that connects multiple devices to a network by using packet switching to receive and forward data to the destination device.