A box contains the following numbered tickets: 1,1,5,9,9
a) If I draw two tickets with replacement, what is the chance that the sum of the two tickets is greater than or equal to 10?
b) Drawing three tickets without replacement, what is the chance the first two tickets are not 5's, and the last ticket is a 5?
c) Calculate b) if the draws are made with replacement.
d) If I repeat the procedure in a) 8 times (ie draw 2 tickets and find their sum, and do this 8 times), what is the chance that I get a sum greater than or equal to 10 exactly 6 of the 8 times?