Set 12: Exponential Functions

Choice A is correct. Choice A is the correct answer. Calculate the ratio after one time period. 1. Initial: $T_0 = 90°C$. 2. After 10 min: $T = 45°C$. 3. Decay Factor: $b = \frac{45}{90} = 0.5$. Strategic Tip: Decay factor = $\frac{\text{final}}{\text{initial}}$ over one time period. Choice B is incorrect because this would be growth, not decay. Choice C is incorrect because this is the temperature, not the factor. Choice D is incorrect because this doesn't match the ratio.