A mechanic sells a brand of automobile tire that has a life expectancy that is normallydistributed,with a mean life of

33 comma 000

miles and a standard deviation of

2500

miles. He wants to give a guarantee for free replacement of tires thatdon'twear well. How should he word his guarantee if he is willing to replace approximately10%of thetires?

Tires that wear out by

nothing

miles will be replaced free of charge.

(Roundto the nearest mile asneeded.)