It is known that the probability of producing a drill bit of extra-high brittleness (defective) is 0.02 . The bits are packed in boxes of a hundred each. What is the probability that

(a) a box will have no defective bits;

(b) the number of defective bits will be less than 3.

How many bits have to be put in a box so that there should be at least 100 good bits with a probability not less than 0.9 ?

Hint. Take advantage of the Poisson distribution.