Statistics ,

in a table of random digits, each digit is to occur with a probability of 0.1.
a) a student examines a list of 200 random digits and counts only eleven 4s and thus claims that the table is not really random. explain the error in the student's thinking.
b) how many 7s would you expect to find in a random digit table consisting of 1,000 digits?

i think b) might be 100 because it says the probability of every number is 0.1, which is 10%, and 10% of 1,000 is 100. can someone and explain both of these? so !