Question

Water in a canal 30 cm wide and 12 cm deep, is flowing with a velocity of l00 km per hour.How much area will it irrigate in 30 minutes if 8 cm of standing water is desired?

Answer 1

Given that,
Water in the canal forms a cuboid of

width `(h)=300cm=3m`

`height  = 12 cm = 1.2 m`

length of cuboid is equal to the distance travelled in 30 min with the speed of 100 km per hour

 ∴ length of cuboid  = `100xx 30/60km=50000 meters`

So, volume of water to be used for irrigation = `50000xx3xx1.2m3`

Water accumulated in the field forms a cuboid of base area equal to the area of the field and height equal to `8/(100) meters `

`∴ (Area  of field)xx8/(100)= 50,000xx3xx1.2`

`⇒Area  of  field = (50000xx3xx1.2xx100)/8 `

`2,250000   meters `