T has been observed that the number of instructions executed between page faults is di- rectly proportional to the number of page frames allocated to a program. If the avail- able memory is doubled, the mean interval between page faults is also doubled. Sup- pose that a normal instruction takes 1 microsec, but if a page fault occurs, it takes 2001 μsec (i. e., 2 msec) to handle the fault. If a program takes 60 sec to run, during which time it gets 15,000 page faults, how long would it take to run if twice as much memory were available?