Question

Consider a process execution 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?

Answer 1

$EMAT=P\times S+(1-P)\times M$
X = $P\times D+(1-P)\times M$
X = $P\times D+M-P\times M$
X - M = P (D - M)
P = $\frac{X-M}{D-M}$