1. MATH 310, FALL 2003 (Combinatorial Problem Solving) Lecture 20, Monday, October 20

2. 5.4. Distributions Homework (MATH 310#7M): Read 5.5 Do 5.4: All odd numbered exercises. Turn in 5.3: 10,26,30,44 Volunteers: ____________ Problem: 44.

3. Two observations Distributions of distinct objects are equivalent to arrangements. Distributions of identical objects are equivalent to selections.

4. Equivalent Forms for Selection with Repetirion The number of ways to select r objects with repetition from n different types of objects. The number of ways to distribute r identical objects into n distinct boxes. The number of nonnegative solutions to x 1 + x 2 +... + x n = r.