\documentclass[12pt]{article} \usepackage{comment} \usepackage{amsmath} \usepackage{amssymb} % for \nmid \newcommand{\D}{{\mathbb D}} \newcommand{\G}{{\mathbb G}} \newcommand{\Z}{{\mathbb Z}} \newcommand{\N}{{\mathbb N}} \newcommand{\Q}{{\mathbb Q}} \newcommand{\R}{{\mathbb R}} \newcommand{\succc}{{\rm succ}} \newcommand{\pred}{{\rm pred}} \newcommand{\lc}{\left\lceil} \newcommand{\rc}{\right\rceil} \newcommand{\Ceil}[1]{\left\lceil {#1}\right\rceil} \newcommand{\ceil}[1]{\left\lceil {#1}\right\rceil} \newcommand{\floor}[1]{\left\lfloor{#1}\right\rfloor} \begin{document} \centerline{Homework 10 MORALLY Due April 28} \begin{enumerate} \item (0 points) What is your name. \vfill \centerline{\bf GO TO THE NEXT PAGE} \newpage \item (10 points) \begin{enumerate} \item (10 points) Show that $$\binom{n}{k} = \binom{n-1}{k-1} + \binom{n-1}{k}$$ with a combinatorial proof. (Hint: Show that the RHS solves the question of how many ways to choose $k$ objects out of $n$ objects.) \item (0 points but you'll need this for a later problem on this HW set and maybe later in life as well.) By convention $(\forall n\ge 0)[\binom{n}{0}=1]$ and $(\forall k\ge 1)[\binom{0}{k}=0]$. From Part 1 that $\binom{n}{k} = \binom{n-1}{k-1} + \binom{n-1}{k}$. Use these two equations to write a program that will do the following: Given $N,K$ outputs $\binom{k}{n}$ for all $0\le k\le K$ and $0\le n\le N$. Run this program for $N=52$ and $K=6$. \end{enumerate} \vfill \centerline{\bf GO TO THE NEXT PAGE} \newpage \item (30 points) Oliver-Poker is poker with a normal deck, but each player gets SIX cards. For all questions here answer it BOTH in terms of binomial coefficient (e.g., $$\frac{\binom{12}{8}}{{\binom{52}{6}}}$$ ) and as an actual number to four places (e.g., 0.2192). (For that you will use the output of the program you wrote in Problem 2.) \begin{enumerate} \item (10 points) What is the probability of getting three 2-of-a-kinds? \newcommand{\he}{\heartsuit} \newcommand{\spa}{\spadesuit} \newcommand{\cl}{\clubsuit} \newcommand{\di}{\diamondsuit} Example: $(2\he, 2\spa, 4\he, 4\di, 8\spa, 8\cl)$ is three 2-of-a-kind. Counterexample: $(2\he, 2\spa, 2\cl, 2\di, 8\spa, 8\cl)$ DOES NOT count as three 2-of-a-kind. \item (10 points) What is the probability of getting a 2-of-a-kind and a 4-of-a-kind? Example: $(2\he, 2\sp, 2\he, 2\di, 8\sp, 8\cl)$ is a 4-of-a-kind and a 2-of-a-kind. \item (10 points) What is the probability of getting a two 3-of-a-kind? Example: $(2\he, 2\spa, 2\he, 8\di, 8\spa, 8\cl)$ is two 3-of-a-kind. \item (0 points) Once its approved Oliver (also called {\it Poptart}) will be teaching a STIC on Poker (real poker, not this problem). Consider taking it!! \end{enumerate} \vfill \centerline{\bf GO TO THE NEXT PAGE} \newpage \item (30 points) Show that there is no way to load two 8-sided dice to get fair sums. \vfill \centerline{\bf GO TO THE NEXT PAGE} \newpage \item (30 points) \begin{enumerate} \item (0 points but you have to do it) Bill throws 2 fair 8-sided dice that are labeled in the normal way (each dice has faces with 1,2,3,4,5,6,7,8). For each $0\le 2\le 16$, give the probability of the sum of the dice being $i$. \item (30 points) Give two 8-sided dice that are NOT labelled $(1,2,3,4,5,6,7,8)$. which, when rolled, give the same probabilities from Part $a$. (The labels have to all be natural numbers that are $\ge 1$.) \end{enumerate} \end{enumerate} \end{document}