Question

Water is flowing at the rate of 15 km/hr through a pipe of diameter 14 cm into a cubiodal pond which is 50 m long and 44 m wide. In what time the level of water in pond rise by 21 cm?

Answer 1

Rate of flow of water× 3.14× (14 × 0.01)^2 = 50 × 21 × 44
50/12 × 22/7 × 14/100 × 14/100 × t = 50 × 21 × 44
On solving for t we get,
t = 180000 s
= 3000 min
= 50 hours

Answer 2

Step-by-step explanation:

Answer:

→ Time = 2 hours .

Step-by-step explanation:

Suppose, the level of water in the pond rises by 21 cm in 'x' hours.

→ Speed of water flowing through a pipe = 15 km/hr .

→ Diameter of the pipe = 14/100 m .

Then, Radius of the pipe (r) = 7/100 m .

∵ Volume of water flowing out of the pipe in 1 hour

= πr²h .

= (22/7) x (7/100) x (7/100) x 15000 .

= 231 m³ .

→

Volume of water flowing out of the pipe in 'x' hours = 231x m³.

∵ Volume of water in the cuboidal pond = lbh .

= 50 x 44 x (21/100) .

= 462 m³ .

∵ Volume of water flowing out of the pipe in 'x' hours = Volume of water in the cuboidal pond raised by 21 cm .

∵ 231x = 462 .

⇒ x = $\frac{462}{231}$

∴ x = 2 .

Therefore, the required time is 2 hours