Question

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

Answer 1

Breadth of a canal, b = 6 m

Height, h = 1.5 m

Speed of water = 10 km/hr

Quantity of water = 8 cm

Quantity of water flowing in 30 minutes?

Volume of water flowing in 60 minutes,

= (10 x 1000) x 6 x 1.5 cm${}^3$

($\because$ Speed = 10 km/hr; 10 x 1000 m/hr)

Volume of water flowing in 30 minutes,

$=1000\times 9\times \frac{30}{60}{m}^3$

$\therefore$ Let the area of land be 'x' sq. m.

$\therefore x\times \frac{8}{100}=45000(\because 8cm=\frac{8}{100}m)$

$x=\frac{4500000}{8}$

$x=562500$ sq.m.

$x=\frac{562500}{10000}$ Hectare

$x=562500$ sq.m.