Water is flowing at the rate …

By the question,Water is flowing at the rate of 15 km/hr through a cylindrical pipe of diameter 14 cm into a cuboidal pond which is 50 m long and 44 m wide

Speed of water flowing through the pipe

{tex}= 15 \mathrm { km } / \mathrm { hr } = 15000 \mathrm { m } / \mathrm { hr }{/tex}

Volume of water flowing in 1 hr

{tex}= \pi R ^ { 2 } H{/tex}

{tex}= \frac { 22 } { 7 } \times \frac { 7 } { 100 } \times \frac { 7 } { 100 } \times 15000 \mathrm { m } ^ { 3 }{/tex}

{tex}= 231 \mathrm { m } ^ { 3 }{/tex}

Volume of water in the tank when the depth is 21 cm

{tex}= l b h = 50 \times 44 \times \frac { 21 } { 100 } \mathrm { m } ^ { 3 }{/tex}

{tex}= 462 \mathrm { m } ^ { 3 }{/tex}

{tex}\therefore{/tex} Time taken to fill {tex}462 \mathrm { m } ^ { 3 }{/tex}

{tex}= \frac { 462 } { 231 } = 2 \mathrm { hrs }{/tex}