A process for making plate glass produces small bubbles (imperfections) scattered at random in the glass, at an average rate of four small bubbles per 10 m. Assuming a Poisson model for the number of small bubbles, determine, to three decimal places, the probability that a piece of glass 2.2 m x 3.0 m will contain

(a) exactly two small bubbles,

(b) at least one small bubble,

(c) at most two small bubbles. Show that the probability that five pieces of glass, each 2.5 m by 2.0 m, will all be free of small bubbles is e-fo Find, to three decimal places, the probability that five pieces of glass, each 2.5 m by 2.0 m, will contain a total of at least ten small bubbles. (L)