1) A speed walker covered 4 1/2 mi in 3/4 hour. How far will he walk with the same pace in 2 hours? 3 hours? 3.5 hours?

2) Two combine harvesters are able to harvest the crop from 320 acres in a certain amount of time. Working together for the same time, how many acres can be harvested by 7 combine-harvesters? 12?

Please explain your work, Thanks!