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Mukesh walks around a circular track of radius 14 m with a speed of 4 km/hr. If he takes 20 rounds of the track, for how long does he walk?

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Question

Mukesh walks around a circular track of radius 14 m with a speed of 4 km/hr. If he takes 20 rounds of the track, for how long does he walk?

Sum
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Solution

Radius of the circular track = 14 m

Circumference of the circular track = 2πr

= `2 xx 22/7 xx 14`

= 44 × 2

= 88 m

Total distance cover in 20 rounds = 88 × 20 = 1760 m

Speed of Mukesh on the circular track = 4 km/h

= `(4 xx 1000)/60`

= `(2 xx 100)/3`

= `200/3` m/min

Time taken by Mukesh = `1760/(200/3)`

= `(1760 xx 3)/200`

= `(176 xx 3)/20`

= 26.4 min

26.4 min = 26 min and 24 s

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Chapter 11: Mensuration - Exercise [Page 352]

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NCERT Exemplar Mathematics Exemplar [English] Class 8
Chapter 11 Mensuration
Exercise | Q 68. | Page 352

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