In a demand paging memory system, page table is held in registers. The time taken to service a page fault is $8$ m.sec. if an empty frame is available or if the replaced page is not modified, and it takes $20$ m.secs., if the replaced page is modified. What is the average access time to service a page fault assuming that the page to be replaced is modified $70$% of the time ?
- $11.6$ m.sec.
- $16.4$ m.sec.
- $28$ m.sec.
- $14$ m.sec.