4.58 A lock on a bank vault consists of three dials, each with 30 positions. In order for the vault to open, each of the three dials must be in the correct position. a. How many different possible dial combinations are there for this lock? b. What is the probability that if you randomly select a position on each dial, you will be able to open the bank vault? c. Explain why "dial combinations" are not mathematical combinations expressed by Equation (4.14).

COUNTING RULE 2 If there are events on the first trial, events on the second trial, . . . , and events on the nth trial, then the number of possible outcomes is (k (4.11) 1)(k2)...(kn)

4.60 A particular brand of women's jeans is available in seven different sizes, three different colors, and three different styles. How many different jeans does the store manager need to order to have one pair of each type?

4.62 If each letter is used once, how many different four letter "words" can be made from the letters E, L, O, and V?

4.70 A reading list for a course contains 20 articles. How many ways are there to choose 3 articles from this list?