Question

Water in a canal, $6m$ wide and $3m$ deep, is flowing with a sped of $10km/h$. How much area will it irrigate in $30$ minutes, if $8cm$ of standing water is needed?

Answer 1

Given;-

width$=6m$

deep$=3m$

speed$=10km/hr=10000m/hr$

speed of water flow in $1$ hour = speed$\times$width$\times$depth

$=10000\times 6\times 3$

$=180000m^3$

volume of water flow in $30min$ $=\frac{1}{2}\times$volume of water flow in hour

$=\frac{1}{2}\times 180000$

$90000m^3$

volume of water irrigated $=$volume of water flow in $30$min

volume of water irrigated $=$base area$\times$height

base area $\times 8cm=$ base area $\times 0.08$

$90000=$ base area $\times 0.08$

base area $\begin{array}{c}=\frac{90000}{0.08}\\ =1125000m^2\end{array}$

hence,

$1125000m^2$ area will it irrigate in $30$min.