3

Set 5: Exponential Functions (Advanced)

Explanation

Answer: A

For h(x)=15(1.08)xh(x) = 15(1.08)^x, approximately how many times larger is h(20)h(20) than h(10)h(10)?

A.

About 2.2 times

✓ Correct
B.

About 10 times

C.

About 1.08 times

D.

Exactly 2 times

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Calculate the ratio. 1. Ratio: h(20)h(10)=15(1.08)2015(1.08)10=(1.08)10\frac{h(20)}{h(10)} = \frac{15(1.08)^{20}}{15(1.08)^{10}} = (1.08)^{10}. 2. Estimate: (1.08)102.162.2(1.08)^{10} \approx 2.16 \approx 2.2. 3. Conclusion: h(20)h(20) is about 2.2 times larger. Strategic Tip: For ratios, factors divide out, leaving a power of the base. Choice B is incorrect because the difference in inputs (10) is not the multiplication factor. Choice C is incorrect because this is just one step, not 10 steps. Choice D is incorrect because (1.08)102(1.08)^{10} \neq 2 exactly.

Key Steps:

The correct answer is About 2.2 times

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

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