Water in a canal 1.5 m wide and 6 m deep is flowing with a speed of 10 km/hr. How much area will it irrigate in 30 minutes if 8 cm of standing water is desired?
Speed of flowing water =10 km/hr
In 30 minutes length of flowing water =10× 
km
= 5 km = 5000 m
Volume of flowing water in 30 minutes =5000 × width × depth
Width of canal = 1.5 m
Depth of canal = 6 m
Volume of canal =5000 × 1.5 × 6 m3
= 45000 m3
Irrigated area in 30 minutes if 8 cm of flowing water is required 
= 562500 m2
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