a. b. C. (3%) Suppose a computer contained 1024 MB of main memory, and operating system needed to create a virtual memory of twice that size using pages of 4KB. How many pages would be required? (1MB=1024KB) 1.14 (3%) Suppose a multiprogramming operating system is allotting time slices of 50 milliseconds. If it normally takes 9 milliseconds to position a disk's read/write head over the desired track and another 16 milliseconds for the desired data to rotate around to the read/write head, what percentage of a program's time slice can be spent waiting for a read/write operation from a disk to take place (not including the time required to actually transfer the data)? (3%) If the machine is capable of executing 10 instructions each nanosecond, how many instructions can be executed during this waiting period?