Question

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 min, if 10 cm of standing water is required for irrigation?

Answer 1

Given,

Breadth = 5.4 m

Height = 1.8 m

Speed of canal = 25 km/hr


Length of canal in 1 hour = 25 km

Length of canal in 60 minutes = 25 km

Length of canal in 1 min = 1/60 * 25

Length of canal in 40 min = 40/60 * 25

= 16.67 km

= 16670 m


Volume of canal = Length * Breadth * Height

= 16670 * 5.4 * 1.8 m³


Volume of water in canal = Volume of area irrigated

Volume of water in canal = Area irrigated * Height

16670 * 5.4 * 1.8 m³ = Area irrigated * 10 cm

16670 * 5.4 * 1.8 m³ = Area irrigated * 10/100 m

16670 * 5.4 * 1.8 * 100 / 10 = Area irrigated

Area irrigated = 1620324 m²

Area irrigated = 1620324/10000 hectares

= 162.0324 hectares Ans.

Ans.) 162.0324 hectares area can it irrigate.

Answer 2

Hi there !!


Breadth , b = 5.4 m

Height[depth] , h = 1.8 m

Speed of canal = 25 km/hr


Length of canal in 1 hour = 25 km


Length of canal in 60 minutes = 25 km                         [ 1 hr = 60 min ]

Length of canal in 1 min = $\frac{25}{60}$

Length of canal in 40 min =$\frac{25}{60}$ × 40

                                          = 16.67 km [ approx . ]

                                          = 16670 m


Volume of canal =  l b h 

                           = 16670  × 5.4  × 1.8 m
                          
                           = 162032.4 metres

Height of standing water = 10 cm = 0.1 metres

Volume of water in canal = Volume of area irrigated

Volume of area irrigated = Area irrigated × height

162032.4 metres = Area irrigated × 0.1

Area irrigated =   162032.4 ÷ 0.1
                       
                      = 1620324 m²

1m² = 0.0001 hectares 

Area irrigated =  162.0324 hectares