Question

Water in a canal, 6 m wide and 1.5 m deep, is flowing with a speed of 10 km/h. How much area will it irrigate (in $m^2$) in 30 minutes, if 8 cm of standing water is needed?

• A. 562500
• B. 625500
• C. 526500
• D. 256500

Answer 1

The correct option is A

562500

Canal is in the shape of a cuboid, where breadth = 6 m and height = 1.5 m.
Speed of water flowing through canal = 10 km/h = 10, 000 m/h
i.e., length of the canal in one hour = 10, 000 m/h

Volume of water flowing through canal in 1 hour
$=length\times breadth\times height=10,000\times 6\times 1.5=90,000m^3$

Volume of water flowing through canal in 30 minutes
$=\frac{90000}{2}=45,000m^3$

Given, height of the standing water = 8 cm = 0.08 m

Now, volume of water in the canal = volume of area that will be irrigated
i.e., volume of water in the canal
= Area that will be irrigated × height of standing water
$\Rightarrow 45000=Areathatwillbeirrigated\times 0.08\Rightarrow Areathatwillbeirrigated=\frac{45000}{0.08}=562500m^2$