Question

Dr. Richard Carr has an old Toyota Camry that is nearing half a million miles driven. If the average Camry lasts only 200,000 miles and the standard deviation is 45,000, to what percentage of cars does Dr. Carr's long lived car belong to?

Answer 1

µ =    200000              
σ =    45000              
                  
P ( X ≥   500000.00   ) = P( (X-µ)/σ ≥ (500000-200000) / 45000)          
= P(Z ≥   6.667   ) = P( Z <   -6.667   ) =    0.0000000000131 = 0.0000000013% of car.

So Richard Carr cars would be rare and only   0.0000000013% of car.

Please revert back in case of any doubt.

Please upvote. Thanks in advance.