1. The blood groups of 1000 people are distributed as follows: 250 people have type A blood;165 people have type B blood;370people have type O blood;and,215people have type AB blood.If a person from this group of 1000peopleis selected at random,what is the probability that this person has type O blood?

2. How many ways canyou arrange the letters in the word BIOSTATISTICS?

3. Let A and B be two events.Suppose the probability that neither A or B occurs is 2/3.What is the probability that one or both occur?

4. A lab product code consists of five letters(A-Z) followed by six numerical digits(0-9).How many lab product codes are possible if:a) there are no restrictions(repetition is allowed)?b) all letters and numbers are different(repetition is not allowed)?

5. Biology competition has 10 participants.The first-place participant gets a gold medal, the second-place participant gets a silver medal, and the third-place participant gets a bronze medal.Of the remaining participants, the next top three finishers get a certificate.

How many ways can the prizes be disbursed?[HINT:The top three positions are different from one another.Of the remaining 7 participants, the top 3 are given a certificate, implying that there is no internal ordering of the position.]