Question

if i plow at 7km/hr and my plow is 1800mm how long will it take to plow one ha

Answer 1

1800 mm
= 180 cm
= 1.8 m

Consider 1 ha as 100 m by 100 m
Assume the plough does swaths of 1.8 m up and down.
100/1.8 = 500/9 runs each 100 m long have to be ploughed
total distance = (500/9)(100) m

time = distance/rate
= (500/9)(100) m / 7 km/h
= (500/9)(100) m / 7000 m/h
= .7936 hrs
= appr 48 minutes

( 1 ha = 10,000 m^2.
I conveniently used 100*100, I could have used any other combination to yield 10,000
e.g. suppose my 1 ha is 400 by 25
repeating the above calculations:
400/1.8 = 2000/9
total distance = (2000/9)(25)
total time = (2000/9)(25) / 7000 = .7936...)