The value of a painting recently sold at an auction can be modeled by the function

. The exponential function models the relationship between the value of the painting,
, in dollars, and the number of years,
, since the painting was sold at the auction.

Which statement correctly interprets this model?
A.
Each year the painting increases its value by 12,000 percent.

B.
The painting was sold at the auction 12,000 years ago.

C.
Each year the painting increases its value by 15 percent.

D.
The painting was sold at the auction 1.15 years ago.

1 answer

To appropriately interpret the model, we need to look at the characteristics of an exponential growth function, typically represented in the form \( V(t) = V_0 \times e^{rt} \) or \( V(t) = V_0 \times (1 + r)^t \), where:

  • \( V(t) \) is the value at time \( t \),
  • \( V_0 \) is the initial value,
  • \( r \) is the growth rate (expressed as a decimal),
  • \( t \) is the number of years.

If the function indicates that the painting's value increases by a certain percentage (like 15%), it would mean that each year the value is multiplied by 1.15 (which translates to a 15% increase).

Evaluating the answer choices:

A. Each year the painting increases its value by 12,000 percent.

  • This is incorrect as 12,000% increase is unrealistically high for an annual increase.

B. The painting was sold at the auction 12,000 years ago.

  • This is incorrect as it provides a specific past time that is unrelated to the model.

C. Each year the painting increases its value by 15 percent.

  • This statement would be correct given that a common interpretation of exponential growth with \( r = 0.15 \) (15%) means that each year the value is multiplied by 1.15.

D. The painting was sold at the auction 1.15 years ago.

  • This statement incorrectly interprets a numerical value in a context that does not correlate to the time elapsed since the auction.

Given this analysis, if the model indeed indicates a growth rate consistent with 15%, then the correct interpretation would be:

C. Each year the painting increases its value by 15 percent.