Microbes in a certain colony exposed to radiation have a 1=6 chance of being

mutated.
a. If ten microbes from the colony are sampled, what is the probability that exactly 4
will be mutated?
b. If ten microbes from the colony are sampled, what is the probability that at most 4
will be mutated?
c. If microbe from the colony is examined one by one, what is the probability that the
�rst mutated microbe is the �fth one that is examined?
d. If microbe from the colony is examined one by one, what is the probability that the
�fth mutated microbes is the tenth one that is examined?