A Galapagos cactus finch population increases by half every decade. The number of finches is modeled by the expression 45 • 1.5^d, where d is the number of decades after the population was measured. Evaluate the expression to find the number of finches for d = –2.

Question

A Galapagos cactus finch population increases by half every decade. The number of finches is modeled by the expression 45 • 1.5^d, where d is the number of decades after the population was measured. Evaluate the expression to find the number of finches for d = –2.

(1 point)
Responses

20

68

900

4,556

Answer 1

To evaluate the expression for d = -2, we substitute -2 for d in the expression:

45 * 1.5^(-2)

1.5^(-2) is equal to 1/1.5^2, which is 1/2.25

So the expression becomes:

45 * 1/2.25

45 divided by 2.25 is equal to 20.

Therefore, the number of finches for d = -2 is 20.

So the correct answer is 20.