The water in a canal, $30 dm$ wide and $12 dm$ deep, is flowing with a velocity of $20 km$ per hour. How much area will it irrigate in $30 minutes$ , if $9 cm .$ Is standing water desired ____

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Detailed Solution

We must first change the units from dm to m in order to answer the given question. In order to determine the area that the water is irrigating, we must first calculate the amount of water flowing through the canal at the given time and speed, given the canal's width and depth.
Equation used:
Decimeters are converted into centimeters as follows:

1 dm = 10 cm

.
The unit is changed from centimeter to meter as follows:

100 cm = 1 m

.
The unit is changed from kilometers to meters as follows:

1 km = 1000 m

.
We know that water in a canal forms a cuboid
The dimensions are
Breadth = 30dm = 3m
Height = 12dm = 1.2m
We know that
Length = distance covered by water in 3 minutes = velocity of water in m/hr × time in hours
By substituting the values
Length = 20000 × (

\frac{30}{60}

)
So we get
Length = 10000m
We know that
Volume of water flown in 30 minutes = l × b × h
By substituting the values
Volume of water flown in 30 minutes = 10000 × 3 × 1.2 = 36000