What is the exponential function that best models the number of gnats the scientists have gathered after the number of hours listed in the table below?

Option A

f(x) = 12.5(1.6)^x

Step-by-step explanation:

The number of gnats the scientists have gathered

At 0 hours, they gathered 12 gnats.

Checking all the options, applying x = 0 makes the index part become 1 (Anything raised to the power zero is 1).

So, we have the following functions

f(x) = 12.5

f(x) = 12.6

f(x) = 6.2

f(x) = 1.6

This has reduced our work, as we can screen out options C and D, they are too far from 12. This leaves us with option A and B.

At 1 hour, they gathered 20 gnats.

Checking options A and B

A. f(x) = 12.5(1.6)

= 20

B. f(x) = 12.6(6.2)

By inspection, 12 × 6 is already 72,

12.6 × 6.2 will be more.

By these, we can conclude that f(x) = 12.5(1.6)^x has the best models the number of gnats the scientists have gathered after the number of hours listed in the given table.