Math Problem Statement

A bacteria culture initially contains 2000 bacteria and doubles every half hour.

Find the size of the bacterial population after 20 minutes.

Find the size of the bacterial population after 10 hours.

Solution

The bacteria culture's growth can be modeled by an exponential growth equation:

P(t)=P02t/TP(t) = P_0 \cdot 2^{t/T}

Where:

  • P0=2000P_0 = 2000 (initial population),
  • T=0.5T = 0.5 hours (doubling time),
  • tt is the time in hours.

1. Bacterial Population after 20 minutes:

Convert 20 minutes to hours: 20minutes=2060=13hours20 \, \text{minutes} = \frac{20}{60} = \frac{1}{3} \, \text{hours}.

Substitute into the formula: P(13)=20002130.5=2000223.P\left(\frac{1}{3}\right) = 2000 \cdot 2^{\frac{\frac{1}{3}}{0.5}} = 2000 \cdot 2^{\frac{2}{3}}.

Use 2231.58742^{\frac{2}{3}} \approx 1.5874: P(13)20001.5874=3174.8.P\left(\frac{1}{3}\right) \approx 2000 \cdot 1.5874 = 3174.8.

The population after 20 minutes is approximately 3175 bacteria.


2. Bacterial Population after 10 hours:

Substitute t=10t = 10 into the formula: P(10)=20002100.5=2000220.P(10) = 2000 \cdot 2^{\frac{10}{0.5}} = 2000 \cdot 2^{20}.

Calculate 220=1,048,5762^{20} = 1,048,576: P(10)=20001,048,576=2,097,152,000.P(10) = 2000 \cdot 1,048,576 = 2,097,152,000.

The population after 10 hours is 2,097,152,000 bacteria.


Would you like further details? Here are 5 related questions to delve deeper:

  1. How does the doubling time affect the population growth rate?
  2. What is the general formula for exponential growth?
  3. How do you calculate population sizes for arbitrary times not aligned with the doubling interval?
  4. What happens to the population size as time approaches infinity?
  5. Can this growth be modeled logarithmically to reverse engineer the time?

Tip: Always check units of time when substituting into growth formulas!

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Math Problem Analysis

Mathematical Concepts

Exponential Growth
Time Conversion
Logarithmic and Exponential Functions

Formulas

P(t) = P0 * 2^(t/T)
Time conversion: minutes to hours

Theorems

Properties of Exponents

Suitable Grade Level

Grades 9-12