Question

As a health worker you need to identify a particular bacteria. You place a drop of the culture on a Petri dish at 9:30 AM to incubate. The chart shows the growth rate of three different bacteria. At 12 PM you need to measure the diameter of the growth and find it to be about 1 cm. Which bacteria would you say the sample is?

A, B, C, or none of those listed?

Answer 1

The time duration between 9:30 AM and 12:00 PM is 2.5 hours.
From the graph, we want the diameter, d, to be 1 cm when the time, t, is 2.5 hours.

Graph A yields d = 1.0 when t = 2.5. CORRECT
Graph B yields about d = 0.6 when t = 2.5. INCORRECT
Graph C yields about d = 0.48 when t = 2.5 INCORRECT

Answer: The bacteria is in sample A.