Question

Water in 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 $30$ minutes, if $8$ cm of standing water is needed?

Answer 1

Given, Breadth $=1.5$ m, Depth/height $=6$ m, speed $=10$ km/h

length of canal in $1$ hour $=10$ km

length of canal in $30$ min $=\frac{30\times 10}{60}=5$ km $=5000$ m

Volume of canal $=l\times b\times h$

Volume of water that flows through the canal in $30$ mins is

$6\times 1.5\times 5000=45000m^3$

Volume of water = $area\times height$

Volume of water = $area\times 0.08m^3$

$area=\frac{45000}{0.08}=562500m^2$