Set 7: Exponential Functions

Choice A is correct. Choice A is the correct answer. Apply the doubling pattern. 1. Doubling periods: $\frac{27}{9} = 3$ periods. 2. After each doubling: Multiply by 2. 3. After 3 doublings: $3000\times 2^3 = 3000 \times 8 = 24,000$. 4. Formula: $A(t) = 3000(2)^{t/9}$. Strategic Tip: 3 doublings = multiply by $2^3 = 8$. Choice B is incorrect because this is after 2 doublings (18 years). Choice C is incorrect because this is after only 1 doubling (9 years). Choice D is incorrect because this is the wrong calculation.