Question

A river 15m deep 50m wide is flowing at the rate of 2 cm per second how many litres of water will fall from the river into the sea in 9 hours

Answer 1

$15 \times 50 \times (2 \div 100) \times 3600 \times 9 = 486000 \: {m}^{3} = 4.86 \times {10}^{8} litres$

15×50×(2÷100) is the volume of water falling into the sea in one second.

There are 3600 seconds in one hour and we have to find the volume falling in 9 hours.

The product is in metre cube so to convert it into litres-

$1 \: {m}^{3} = {10}^{ - 3} \: litres$