1) A random number generator is used to select an integer from 1
to 50. Since random number generator generates any number randomly,
all the numbers from 1 to 50 get equal chance to occur.
Thus if X denote the random number selected by using the random
number generator, then,
P(X=k) =1/50, k=1, 2,...,50,i.e., X follows a discrete uniform
Thus, P(X=13) =1/50=0.02.
Thus, the required probability is 0.02.
2) Given, there are 19 DVRs among 100 DVRs which are known to be
Thus, there are 81 non defective DVRs and any one of them can be
chosen in 81C1=81 possible ways.
Again any one DVR from 100 DVR can be chosen in
100C1=100 possible ways.
Thus, the probability of randomly selecting a non defective DVR
Thus the required probability is 0.81.