Step-1 Find the number of enteries in page table
No of enteries in page table = virtual address space / page size = 248/214 = 234
Step-2 Find number of frames in physical memory
No of Frames = 234/214=220
So we need 20 bits + 2 additional bits for protection = 22 bits
22 bits = 2.75 bytes
Therefore size of page table = 234 x 2.75 =44 GB Approx