I need help answering a homework problem

Question

A manufacturer knows that their items have a normally distributed lifespan, with a mean of 4.5 years, and standard deviation of 1.3 years.

The 2% of items with the shortest lifespan will last less than how many years?

Answer 1

use formula for standardized variable

z = (x - mean)/SD, where x = lifespan, mean = 4.5, and SD = 1.3

Find z score corresponding to 0.02 probability.

plug that z score along with given mean and SD into the above equation and solve for x.