Here's the problem::

"A certain kind of tire is known to begin showing wear when it has been driven for 16,500 miles on the average with a standard deviation of 3,300 miles. If a car rental agency buys 36 of these tires for replacement purposes and puts each one on a different car, what are the probabilities that the 36 tires will average."

i couldn't really get the question... it's either i'm very bad at english or i'm very bad at analyzing. In any case, I also find it quite confusing having 2 units (miles and tires)

In urgent need... Help greatly appreciated!