Table

Corning Corporation produces three types of high quality glasses that are supplied to many companies such as Apple. The annual demand for all these types and their corresponding probabilities for the year $2021$ are as follows.

$\backslash$table$[[$Variets$,$Demand in thousands of tons,Probability$],[$I$,600,000,0\mathrm{.}3],[$II$,200,000,0\mathrm{.}4],[$III$,300,000,0\mathrm{.}3]]$

Assuming that all the three types can be manufactured in the same plant having a capacity of $500,000$ tons.

How much of a capacity cushion is there?