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Q.) A horse take $\frac { 5 }{ 2 } $ seconds to complete a round around a circular field. If the speed of the horse was 66 m/sec, then the radius of the field is,[Given $\Pi =\frac { 22 }{ 7 } $]

(a) 25.62 m

(b) 26.52 m

(c) 25.26 m

(d) 26.25 m

Solution:

Speed of the horse was 66 m/sec.

total distance travelled in $\frac { 5 }{ 2 } $ seconds = $\frac { 5 }{ 2 } $ X 66 = 165 metres

This will be equal to the circumference of the Circle.

$2\Pi r$= 165

=> $2X\frac { 22 }{ 7 } X r $ = 165

=> r = $ \frac { 165X7 }{ 2X22 } $ = 26.25 m

Hence , Option(d)