Question

a river 3m deep and 40m wide is flowing at the rate of 2 km/hour.how much water will fall in to the sea in a minute

Answer 1

Area of cross section of the river = 3 × 40 = 120 m2.
Rate of water flow = 2km/h = (2000/60) m/min
Volume of water flowing through this cross-section in every minute = Area × Rate
= (120)×(2000/60) = 4000 m3 = 4000×106 cc = 40,00,000 Litres.

Answer 2

$\huge{\gray{\boxed{\boxed{\pink{\ulcorner{\mid{\overline{\underline{\bf{Answer:-}}}}}}\mid}}}}$

The river is 3m deep, 40m wide and is flowing at the rate of 2km\hour.

$\sf\red{The \: length \: of \: water \: flow \: in \: 1min= \frac{2000}{60} }$

$\sf\pink{ = \frac{100}{3}m }$

$\sf\gray{Therefore, here \: l = \frac{100}{3}m,b =40m \: and \: h = 3m }$

$\sf\pink{Thus \: required \: volume \: of \: water= \: \frac{100}{3} \times 40 \times 3 }$

$\sf\gray{ = 4000 {m}^{3} }$