document.write( "Question 201518: If a tire has a mean mileage of 60,000 miles and a standard deviation of 2,000, and the company doesn't want to have a replacement expense of more than 4%, what is the minimum guaranteed mileage for the tire? \n" ); document.write( "

Algebra.Com's Answer #151778 by stanbon(75887) $\"\"$ $\"About$

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If a tire has a mean mileage of 60,000 miles and a standard deviation of 2,000, and the company doesn't want to have a replacement expense of more than 4%, what is the minimum guaranteed mileage for the tire?
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\n" ); document.write( "Draw the normal curve with center at 60,000.
\n" ); document.write( "Note that sigma = 2000
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\n" ); document.write( "Mark a point in the left tail that has 4$ of the miles driven to the left.
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\n" ); document.write( "Find the z-value of that point using your z-chart or calculator.
\n" ); document.write( "I get InvNorm(0.04) = -1.7507
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\n" ); document.write( "Now find the \"raw score\" corresponding to that z-score using
\n" ); document.write( "x = z*sigma + mu
\n" ); document.write( "x = -1.7507*2000 + 60000
\n" ); document.write( "x = 56498.63 miles
\n" ); document.write( "That is the number of miles for which they should warrant the tires.
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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