# SAVY 2019: Session 4, Day 3 – Puzzles and Problem Solving (Rising 5th/6th)

Posted by on Wednesday, July 10, 2019 in Grade 5, Grade 6, SAVY.

Most of the morning in Puzzles and Problem Solving was spent converting our classroom into an airplane…or at least a room with 15 seats and boarding passes. Consider the following scenario: The first person to board a fully-booked flight drops his or her boarding pass and doesn’t bother to pick it up. The person doesn’t know where to sit and therefore just takes any seat he or she likes.

Everyone else boards the plane and takes his or her assigned seat if it is available. If it is not available, the passenger also takes any available seat he or she likes in the airplane. The question we investigated was, “What is the probability that the last person to board the plane gets to sit in his or her assigned seat?”

Each student got to take a turn as the nice person at the back of the line and the “not-so-nice” person at the front of the line. When asked before the activity what the answer to the question was, most students said 1 out of 15 (or the equivalent 1 out of 100 in the originally stated problem). Then we acted out the problem, and the last person got his or her seat in 8 out of 15 trials! One thing that might be fun would be for you to try out a miniature version of this problem at home.

The actual probability is 50% (a multiple-choice answer that none of the students originally chose), and, somewhat surprisingly, it doesn’t matter how many people and seats are on the airplane, as long as the number of seats is equal to the number of people in line. We will spend more time later in the week discussing the basics of this “Airplane Math.” Our discussion today was mostly conceptual, but we will delve into the calculations that justify this counter-intuitive answer.

We spent a fair amount of the afternoon investigating Sudoku puzzles and learning some tricks and strategies for completing them. Students then worked both individually and in small groups talking about puzzles of varying difficulty. I also look forward to challenging them with more interesting Sudoku puzzles later in the week. We took a brief glimpse into what might lie ahead, and I was impressed by the quality of the comments pertaining to those weird sudokus.

It’s hard to believe that class is more than half over! I am so excited to see what these students come up with over the course of the last two days!