Choice A is the correct answer. Find the half-life.

1. Target: Half of 5000 = 2500.
2. Equation: $2500 = 5000(0.92)^t$, so $(0.92)^t = 0.5$.
3. Test:
   • $t=8$: $(0.92)^8 \approx 0.513$ (close to 0.5) ✓
   • $t=9$: $(0.92)^9 \approx 0.472$ (below 0.5)
4. Answer: About 8 years.

💡 Strategic Tip: For decay factor 0.92, half-life ≈ $\frac{\ln(0.5)}{\ln(0.92)} \approx 8.3$ years.

Choice B is incorrect because decay is faster. Choice C is incorrect because$(0.92)^4 \approx 0.716 eq 0.5$. Choice D is incorrect because$(0.92)^6 \approx 0.606 eq 0.5$.