Question

Water in a rectangular reservoir having base 80 m by 60 m is 6.5 m deep. In what time can the water be emptied by a pipe of which the cross-section is a square of side 20 cm, if the water runs through the pipe at the rate of 15 km/hr.

Answer 1

Given,

Dimension of rectangular reservoir = 80m × 60m

Depth of water in reservoir = 6.5 m

Side of square pipe = 20cm

Rate of flow of water through pipe = 15 km/h

Volume of reservoir = 80 × 60 × 6.5 m³

Volume of pipe = \(\cfrac{20}{100}\times15000\) m³

Let reservoir be emptied in t hours

\(=\cfrac{20}{100}\times\cfrac{20}{100}\times15000\times t\)

= 80 x 60 x 6.5

 = t = \(\cfrac{80\times60\times6.5\times100\times100}{20\times20\times15000}\)

= 52 hours