If Bob goes along the side that's 120 feet long, he will till 110 / 2 = 55 rows.
Each of these rows are 120 feet long, so he will push the tiller a total of 120 * 55 = <<120*55=6600>>6,600 feet.
He tills 1 linear foot of ground every 2 seconds, so it will take him 2 * 6,600 = 13,200 seconds to till this plot
13,200 seconds is 13,2000 / 60 = <<13200/60=220>>220 minutes
#### 220