What does it mean for three events to be mutually exclusive?

Segment ab is shown on the graph. which shows how to find the x-coordinate of the point that will divide ab into a 2: 3 ratio using the formula

Mozart lenses inc. recently introduced seelites, a thinner lens for eyelasses. of a sample of 800 eyeglass wearers, 246 said they would purchases their next pair of eyeglasses with the new lenses. lenses inc. estimates that the number of people who purchase eyeglasses in a year is 1,700,000. most eyeglasses wearer buy one new pair of eyeglasses a year. what is the annual sales potential for the new lenses.

I’m confused on how to work the pie charts