Water flows from a tap into cylindrical container at the rate 5πcm(^3) per second. If the radius of the container is 3cm, calculate the level of water in the container at the end of 9 seconds.
-
A.
2cm -
B.
5cm -
C.
8cm -
D.
15cm
Correct Answer: Option B
Explanation
Volume of water after 9 seconds = (5pi times 9 = 45pi cm^3)
Volume of cylinder = (pi r^2 h)
(therefore pi r^2 h = 45pi)
(pi times 3^2 times h = 45pi)
(implies 9h = 45 )
(h = 5 cm)
(where h = height of the water after 9 secs)