$SP=$

a$.$ User wants to add $256k$ EPROMs and $256k$ SRAMs to a PC using the $74138s$ to decode the $64k8$ memory blocks $($EPROMs and SRAMs$)$ controlled by Ys$.$ Addresses available start $40000H$ and another $C0000.$

How many memory block required from EPROMs and SRAMs?

Determine the typical range address of added EPROMs and SRAMs?

Determine the range of each memory block controlled by Ys$?$

Design and draw the memory decoding using $74138$ circuitries in which the memory block controlled by Ys$?$