Revision as of 16:16, 3 March 2010

HW7MA375S10 - Due Thursday, March 4th

6.4 - 6, 8, 12, 16 | 7.1 - 12, 24, 30, 36, 42, 44, 46

Section 6.4

6.

does the order of winning numbers set matter?

I don't think so. Typically, in a lottery, it's just a combination of numbers, not a permutation. For example, the combination "5, 10, 15, 20, 25, 30" would be the same as "30, 25, 20, 15, 10, 5."

8.

12.

I figured out the probability, but got a little confused about the expectation. Any hints? thanks

Hint: it's a geometric distribution. See pages 433-434 - specifically, Theorem 4 on page 434.

16.

Section 7.1

12.

24.

30.

36. I'm totally lost, help please.

I broke down how many ways can 10 cents, 15 cents, and 20 cents be paid using tree diagram. Then, find the recurrence relation of a20 with respect to the others.

42.

Does anyone have any advice for this one?

44.

46. i got 9 ways to parenthize x_0-x_4. is this correct because part B is confusing.

I don't think that's right. You can use the explicit formula in the example to find the correct number (part c).