Consider a process executing on an operating system that uses demand paging. The average
time for a memory access in the system is M units if the corresponding memory page is
available in memory, and D units if the memory access causes a page fault. It has been
experimentally measured that the average time taken for a memory access in the process is
X units.
Which one of the following is the correct expression for the page fault rate experienced by
the process?
(A) (D – M) / (X – M) (B) (X – M) / (D – M)
(C) (D – X) / (D – M) (D) (X – M) / (D – X)
