Cardo Systems interview questions

He drew me a switch that is responsible for transferring data between devices connected to it via ports. A switch has a number of ports (say 10), and each port can be connected to either a computer or another switch to which other computers are connected. Switches take care of the transfer of packets that consist of a source MAC, destination MAC, and the message itself. The packets must reach the computer with the destination MAC address, and there is no problem if they also reach other computers (they will simply understand that it is not for them and ignore it), but it is less efficient than sending only to the intended computer. With all this information, he gave me a situation in which there was a power outage, as a result of which the switch did not have the memory that included which MAC address was connected to which port. Now a computer with MAC address A, which is connected to port 1, sends a packet intended for a computer with MAC address B, which is connected to port 2. How did the switch know to whom to send the packet?