Question

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Q. Water in a canal, 5.4 m wide and 1.8 m deep, is flowing with a speed of 25 km / hour. How much area can it irrigate in 40 minutes, if 10 cm of standing water is required for irrigation?

Answer 1

Dear student,

$$\begin{gathered} Widthofcanal=5.4m \\ Heightordepthofcanal=1.8m \\ Speedofwaterflowing=25km/hr=25\times 1000m/hr=25000m/hr \\ So,in1hourthelengthofthecanalthatwatertraveledin1hr=25000m \\ Volume=length\times breadth\times height \\ \Rightarrow 25000\times 5.4\times 1.8=243000m^3 \\ soin1hr243000m^{3}ofwaterwillflow \\ soin40min\left(\frac{243000}{60}\times 40\right)m^{3}willflowintothefield \\ So,volumeofwaterinthefield=162000m^3 \\ Asvolume=area\times height \\ Ands\tan dingwaterordepthneeded=10cmor\left(\frac{10}{100}\right)m \\ So,162000m^3=area\times \frac{10}{100} \\ \Rightarrow area=\frac{162000\times 100}{10}{m}^2 \\ \Rightarrow Soareairrigated=1620000m^2 \end{gathered}$$

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