Combinatorial Probability

There are two exercises in my probability and statistics textbook with which I am experiencing difficulty.

**Exercise 1-28** A high school lottery uses two sets of numbered balls. One set consists of ten white balls numbered 1-10 and the second set contains twenty blue balls numbered 1-20. To play, you select two white balls and two blue balls.

(b) Your lottery ticket consists of four numbers: two white numbers, each between 1 and 10 inclusive, and two blue numbers, each between 1 and 20, inclusive. What is the probability that your lottery ticket contains exactly one matching white number and two matching blue numbers?

I know the total number of outcomes is . How would I calculate the number of outcomes resulting in exactly one matching white number and two matching blue numbers (so I can divide that by the number of total outcomes to find the probability)?

**Exercise 1-29** At a picnic, there was a bowl of chocolate candy that had 10 pieces each of Milky Way, Almond Joy, Butterfinger, Nestle Crunch, Snickers, and Kit Kat. Jen grabbed six pieces at random from this bowl of 60 chocolate candies.

(a) What is the probability that she got one of each variety?

There are total outcomes. Of those outcomes, result in one of each variety. Therefore, shouldn't the solution be ? The solution in the back of book is 0.01997.