A rectangular water reservoir of 10.8m by 3.75m at the base. Water flows into it at the rate of 18m/s through a pipe having the cross section 7.5cm*4.5cm. Find the height to which the water rise in the reservoir in 30 minutes?

It is given that a rectangular water reservoir of 10.8 m by 3.75 m at the base. Let height of the water reservoir is h m.

So,

  …… (1)

And water flows into it at the rate of 18m/s through a pipe having the cross section 7.5 cm by 4.5 cm.

Note: Convert cm into m and minute into second.

Total volume of water in the reservoir in 30 minute

  …… (2)

Equating equation (1) and (2), we get,

Hence height of the reservoir will be 2.7 m.