The graph shows the natural logarithm of the temperature of various thermometers as a function of time. The thermometer that cools at the quickest rate is
A) 1
B) 2
C) 3
D) 4
E) 5

Question

The graph shows the natural logarithm of the temperature of various thermometers as a function of time. The thermometer that cools at the quickest rate is
A) 1 
B) 2 
C) 3 
D) 4 
E) 5

Quizplus · Accepted Answer

The thermometer that cools at the quickest rate is the one with the steepest slope on the graph. This corresponds to the thermometer with the largest negative value for its derivative. From the graph, we see that the derivative is the steepest and most negative for thermometer 3. Therefore, choice C is the best answer.

The Graph Shows the Natural Logarithm of the Temperature of Various