This question deals with topic segmented paging....
Segements are divided into pages.Largest size of 1 segment would be 2^9*2^9=256 K words.
As number of pages in segment will be=2^9( as 9 bits used for no.of pages) and each page size as given would be of=2^9(as 9 bits used in offset).So one segment size would be 256K words.
