The same as Q1:Assume the printercartridgesin average can print 12,000 pages with 800 pages as its standard deviation (= 12000, = 800), and it is a bell-shaped distribution for the number of pages (X) it can print before running of of ink.(X is a random variable, isn't it?)

Using Emprical Rules to answer:

What is the chance that your cartridger can print less than 12,800 pages?That means in Math: Prob(X < 12,800) or in short: P(X < 12,800) = ?

(ex., if the answer is 6.5%, write only 0.065, ignore the % sign).