Water running in a cylindrical pipe …

Diameter of cylindrical pipe = 7 cm
∴ Radius of cylindrical pipe = {tex}\frac { 7 } { 2 }{/tex}cm =  3.5 cm
Volume of water flows in 1 min = 192.5 litres
Volume of water that flows per hour = {tex}( 192.50 \times 60 ){/tex}litres
{tex}= ( 192.50 \times 60 \times 1000 ) \mathrm { cm } ^ { 3 }{/tex} ........(I)
{tex}{/tex}  {tex}{/tex}Let h cm be the length of the column of water that flows in one hour.
Clearly, water column forms a cylinder of radius 3.5 cm and length h cm.
{tex}\therefore{/tex} Volume of water that flows in one hour
= πr^{​​​​​2} h
Volume of the cylinder of radius 3.5 cm and length h cm
{tex}= \left[ \frac { 22 } { 7 } \times ( 3.5 ) ^ { 2 } \times h \right] \mathrm { cm } ^ { 3 }{/tex} ...(ii)
From (i) and (ii), we have
πr^{​​​​​2} ​​h = 192.50 × 60 × 1000
{tex}\frac { 22 } { 7 } \times 3.5 \times 3.5 \times h = 192.50 \times 60 \times 1000{/tex}
{tex}\Rightarrow \quad h = \frac { 192.50 \times 60 \times 1000 \times 7 } { 22 \times 3.5 \times 3.5 } \mathrm { cm }{/tex} = 300000 cm = 3 km
Hence, the rate of flow of water is 3 km per hour.