Math Problem Statement

A colony of bacteria is increasing at the rate of 15% each hour. There are 2,500 bacteria in the colony at the time observations begin. Find an exponential growth model for A, the number of bacteria t hrs after the first observation.

Use the model to determine the number of bacteria in the colony 12 hrs after the initial observation. (Round your answer to the nearest whole number.)

Solution

To model the growth of the bacteria colony, we can use the exponential growth formula:

A(t)=A0ertA(t) = A_0 e^{rt}

Where:

  • A(t)A(t) is the population after time tt (in hours),
  • A0A_0 is the initial population (2,500 bacteria),
  • rr is the growth rate per hour (expressed as a decimal),
  • tt is the time in hours.

Step 1: Identify the parameters

  • Initial population A0=2500A_0 = 2500,
  • Growth rate r=15%=0.15r = 15\% = 0.15 per hour.

So, the exponential growth model becomes:

A(t)=2500×e0.15tA(t) = 2500 \times e^{0.15t}

Step 2: Find the population after 12 hours

Now, substitute t=12t = 12 into the equation:

A(12)=2500×e0.15×12A(12) = 2500 \times e^{0.15 \times 12} A(12)=2500×e1.8A(12) = 2500 \times e^{1.8}

Using e1.86.0496e^{1.8} \approx 6.0496:

A(12)2500×6.0496A(12) \approx 2500 \times 6.0496 A(12)15,124A(12) \approx 15,124

Thus, the number of bacteria after 12 hours is approximately 15,124.


Would you like further details or have any other questions? Here are five related questions:

  1. What happens to the bacteria population after 24 hours?
  2. How would the equation change if the growth rate was compounded continuously at 10%?
  3. How long will it take for the population to double in size?
  4. What is the population after 6 hours instead of 12?
  5. How would the model change if the bacteria die off at a rate of 5% per hour?

Tip: Exponential growth processes are often faster than linear ones—small percentage increases can lead to big changes over time!

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Math Problem Analysis

Mathematical Concepts

Exponential Growth
Algebra

Formulas

A(t) = A_0 * e^(rt)

Theorems

Exponential Growth Model

Suitable Grade Level

Grades 10-12