A scientist is growing cells in a petri dish. Which of the following equations could model the number of cells in the petri dish after x days?(1 point) Responses y=100(0.2)x y equals 100 left parenthesis 0.2 right parenthesis superscript x baseline y=(14)x y equals left parenthesis Start Fraction 1 over 4 End Fraction right parenthesis superscript x baseline y=15(0.99)x y equals 15 left parenthesis 0.99 right parenthesis superscript x baseline y=10(2)x

1 answer

To model the growth of a population of cells in a petri dish over time, we typically look for a function that reflects either exponential growth or decay.

  1. Exponential growth is characterized by a base greater than 1 (e.g., \(y = ab^x\) where \(b > 1\)).
  2. Exponential decay is characterized by a base between 0 and 1 (e.g., \(y = ab^x\) where \(0 < b < 1\)).

Given the provided equations:

  1. \(y = 100(0.2)^x\): This represents exponential decay because the base \(0.2 < 1\).
  2. \(y = 14^x\): This represents exponential growth because \(14 > 1\).
  3. \(y = \left(\frac{1}{4}\right)^x\): This represents exponential decay because \(\frac{1}{4} < 1\).
  4. \(y = 15(0.99)^x\): This represents exponential decay because the base \(0.99 < 1\).
  5. \(y = 10(2)^x\): This represents exponential growth because \(2 > 1\).

Based on typical biological growth, the models that more commonly apply are those of exponential growth. Therefore, the equations representing exponential growth from the options provided are:

  • \(y = 14^x\)
  • \(y = 10(2)^x\)

However, if we consider models appropriate for cell growth that include a starting quantity, \(y = 10(2)^x\) and \(y = 14^x\) would be the choices leaning towards growth.

If we need to select one model that best represents cell growth in a petri dish, it would likely be:

\(y = 10(2)^x\), representing a scenario where the cells are doubling each day starting from a quantity of 10.

If you need only one answer, then choose \(y = 10(2)^x\) as a model representing cell growth after x days.