A 2 m deep and 21 m wide river is flowing at the rate of 5 km/h. How many kilolitres of water will fall into the sea in 10 min?

Correct option is A

Given:
Dimension of river = 2m deep and 21m wide.
Speed of river = 5kmph
Formula used :
Area of river = depth × width
Solution:
Flow speed of the river 5 km/h,
we convert this to meters per minute: 5 km/h=5000 m/h
In minutes:
5000 m/h÷60 =83.33 m/min
Distance the water travels in 10 min .
D = 83.33m/min×10min =833.3m
area of the river:
A = depth × width
A = 2m × 21m
 = 42m²
Volume V of water flowing in 10 minutes:
V =  a × d
V =  42m² × 833.3m
= 35000m³
Since 1 m³=1 kilolitre
 35000m³ = 35000kl
Alternate solution:
Area of river = 2 × 21 = 42 sq.m
Flow rate = 5kmph = $$\frac{5000}{60}$$​ = $$\frac{250}3$$​ m/min
Amount of water that falls into the sea in 10 minute = area of river × flow rate × 10
 = 42 × $$\frac{250}3$$​ × 10
= 35000 m³
= 35000 kl