Answer:
The farmer is moving at 10 m / 40 s = .4 m/s
2 min 20 sec = 140 sec
The farmer will have moved 140 * .4 = 56 m
To cover the x-axis twice he will have moved x = 10
56 - 50 = 6 m and he will have moved a distance of 6 on the y-axis
S = (10^2 + 6^2)^1/2 = 11.7 m from the origin