# . A farmer connects a pipe of internal diameter 20 cm from a canal into a cylindrical tank inher

field, which is 10 m in diameter and 2 m deep. If water flows through the pipe at therate of 3 km/h, in how much time will the tank be filled?

Solution:Radius (r1) of circular end of pipe =20/200

= 0.1 m

Area of cross-section =π * r12

= π * (0.1)2

= 0.01 π m2

Speed of water = 3 km/h

= 3000/60

= 300/6

= 50 meter/min

Volume of water that flows in 1 minute from pipe = 50 × 0.01 π

= 0.5π m3

Volume of water that flows in t minutes from pipe = t × 0.5π m3

Radius (r2) of circular end of cylindrical tank =10/2

= 5 m

Depth (h2) of cylindrical tank = 2 m

Let the tank be filled completely in t minutes

Volume of water filled in tank in t minutes is equal to the volume of water flowed in t minutes from the pipe

Volume of water that flows in t minutes from pipe = Volume of water in tank

t× 0.5π = π ×(r2)2 ×h2

t× 0.5 = (5)2 ×2

t = 100

Hence, the cylindrical tank will be filled in 100 minutes