So you want
which can be converted to standard normal using
So
So you should be able to use a standard normal table to calculate this using symmetry..
The tread life of a particular brand of tire is a random variable best described by a normal distribution with a mean of 60,000 miles and a standard deviation of 1400 miles. What is the probability a particular tire of this brand will last longer that 58,600?
what formula do I particularly use here?