Question

A canal is 300 cm wide and 120 cm deep.The water in the canal is flowing with a speed of 20 km/hr. How much area will it irrigate in 20 minutes if 8 cm of standing water is desired?

Answer 1

Width 300cm=3m
depth 120cm=1.2m
speed of canal 20km/h
20×1000 m/h
vol. of water flow in 1 hour = width of canal ×depth of canal ×speef of canal water
3×1.2×20×1000 =72000$m^3$
In 20 min ,volume of water flows = $\frac{72000\times 20}{60}$ = 24000$m^3$
Area irrigated in 20 min = $\frac{2400}{0.08}$ = 300000 $m^2$
30 hectare