Question

Use the following information. Each year in the month of March, the NCAA basketball tournament is held to determine the national champion. At the start of the tournament there are 64 teams, and after each round, one half of the remaining teams are eliminated. How many teams remain after 3 rounds? after 4 rounds?

Short answer

After 3 rounds, 8 teams remain. After 4 rounds, 4 teams remain.

Step-by-step solution

Determine initial number of teams

The tournament begins with 64 teams.

Calculate number of remaining teams after one round

After one round, half of the 64 teams are eliminated. So the number of remaining teams will be \( \frac{64}{2} = 32 \) teams.

Calculate number of remaining teams after two rounds

After the second round, half of the 32 remaining teams are eliminated. So the number of teams will be \( \frac{32}{2} = 16 \) teams.

Calculate number of remaining teams after three rounds

After the third round, half of the 16 remaining teams are eliminated. So the number of remaining teams will be \( \frac{16}{2}= 8 \) teams.

Calculate number of remaining teams after four rounds

After the fourth round, half of the 8 remaining teams are eliminated. So the number of remaining teams will be \( \frac{8}{2} = 4 \) teams.

Key concepts

Exponential Functions

Exponential functions are a fundamental concept in algebra that describe situations where a quantity decreases or increases at a rate proportional to its current value. One of the classic examples of an exponential function is population growth, but it can also model many other phenomena, like radioactive decay or financial investments.

An exponential function can be written in the form of the equation: \( y = a \times b^x \), where \( a \), is the initial value, \( b \), is the base or the growth/decay factor and \( x \), represents time or number of occurrences.

In the problem about the NCAA tournament, the number of teams decreases in each round. This decay can be modeled by the function \( y = 64 \times \frac{1}{2}^x \), where \( x \) is the number of rounds and \( y \) is the number of teams that remain after those rounds. This formula is a real-world application of an exponential decay function, demonstrating how algebra helps us understand and predict outcomes in dynamic systems.

Mathematical Modeling

Mathematical modeling is the process of using mathematics to represent, analyze, and predict real-world behaviors and events. The key to successful modeling is choosing the correct type of function to match the scenario presented. For instance, we use linear functions for constant rates of change, quadratic functions for acceleration, and exponential functions for proportionate rate changes.

In the context of the NCAA basketball tournament problem, we assume a perfect scenario where exactly half of the teams are eliminated in each round uniformly. This makes it a perfect candidate for exponential decay modeling. The provided steps show a direct application of mathematical modeling: First, we identify the initial condition (64 teams), then we define the process (elimination of half the teams after each round), and finally, we translate this into a mathematical equation and carry out calculations for each subsequent round.

Through this modeling, we can predict that after 3 rounds, 8 teams remain, and after 4 rounds, we are left with 4 teams. The power of mathematical modeling is apparent; it simplifies the complex real-world process of the tournament into a predictable and manageable representation.

NCAA Basketball Tournament Problem

The NCAA basketball tournament is an annual event that involves a series of games with a simple 'win or go home' rule. This simplifies the progression of the tournament into a system where the number of teams is halved after each round. This set-up makes for an excellent illustrative example of exponential decay functions.

By understanding the nature of the tournament's structure, we can apply the concept of exponential decay to model how many teams remain after each round. The step by step solution shows how the total number of teams is reduced from 64 to 4 after four rounds. To provide exercise improvement advice, emphasizing the pattern of exponential decay (teams remaining being divided by 2 each round) is key, as is the relation of the rounds to the exponent in the decay formula \( y = 64 \times \frac{1}{2}^x \). Recognizing and using the pattern can simplify calculations and predictions for any round without tediously computing the number of remaining teams after every single round.

This problem also demonstrates the use of algebra in problem-solving, enabling students to apply abstract mathematical principles to practical, real-world situations.