Question

In one fortnight of a given month, there was a rainfall of 10 cm in a river valley. if the area of the valley is 97280 sq.km, show that the total rainfall was approximately equivalent to the addition to the normal water of three rivers each 1072km long, 75m wide and 3m deep. Pls explain each and every step clearly

Answer 1

$heya$
Area of the valley =97280 km²
Height of rainfall in valley = 10cm = 10 × 10⁻⁶ = 10⁻⁵ km
Now, volume of rain water in valley = area of the valley × height of rainfall into valley = 97280 × 10⁻⁵ km³ = 0.9728 km³
Volume of water in valley 0.9728 km³ in 14days [ according to question ]
So, volume of water in valley in 1 day = 0.9728/14 ≈ 0.7 km³

Now, volume of each river = length × Breadth × height
= 1072km × 75m × 3m
= 1072 × 75 × 10⁻³ × 3 × 10⁻³ km³
= 0.2412 km³

So, volume of 3 rivers = 3 × volume of each river
= 3 × 0.2412 km³
= 0.7236 km³ ≈ 0.7 km³

Here it is clear that approximately volume of water in valley {means volume of rainfall water } = volume of water in 3 rivers

Hope it helps to you.