It takes Bonnie 18 minutes to vacuum 2 rooms. Assuming the rooms are the
same size and Bonnie works at the same
speed, about how long will it take her to
vacuum 4 rooms?

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4,999. the drive is currently serving a request at cylinder 2,150, and the previous request was at cylinder 1,805. the queue of pending requests, in fifo order, is: 2069, 1212, 2296, 2800, 544, 1618, 356, 1523, 4965, 3681