The wheels of a car are of diameter 80 cm each..........66km per hour?

1.	The wheels of a car are of diameter 80 cm each..........66km per hour?
Answer» Diameter of the wheel = 80 cm{tex}\\therefore {/tex} Radius of the wheel =\xa0{tex}\\frac { 80 } { 2 } = 40 \\mathrm { cm }{/tex}{tex}\\therefore {/tex}Circum ference of the wheel =\xa0{tex}2 \\pi ( 40 ) \\mathrm { cm } = 80 \\pi \\mathrm { cm }{/tex}{tex}\\therefore {/tex}\xa0Distance covered by the wheel in one complete revolution{tex}= 80 \\pi \\mathrm { cm } = 80 \\times \\frac { 22 } { 7 } \\mathrm { cm } = \\frac { 1760 } { 7 } \\mathrm { cm }{/tex}\xa0Distance covered by the wheel in 1 hour\xa0( = 60 minutes) = 66 km = 6600000 cm{tex}\\therefore {/tex}\xa0Distance covered by the wheel in 10 minutes{tex}= \\frac { 6600000 } { 60 } \\times 10 = 1100000 \\mathrm { cm }{/tex}\xa0{tex}\\therefore {/tex} Required number of complete revolution{tex}= \\frac { 1100000 } { \\frac { 1760 } { 7 } } = \\frac { 1100000 \\times 7 } { 1760 } = 4375{/tex}

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