Final answer:
The amount after 18 months of continuous compounding at 14.3% is approximately $9,294.32. For the investment to double, it would take roughly 4.85 years, highlighting the significant effects of compound interest over time.
Step-by-step explanation:
To address part (a), we calculate the future value (s) after 18 months (1.5 years) using the given formula for continuous compounding, which is s = 7500e0.143t. Substituting 1.5 for t gives us:
s = 7500 e(0.143 × 1.5)
s = 7500 e0.2145
s ≈ 9294.32
For part (b), we want to find the time (t) it takes for the investment to double its original amount. We solve for t in the equation 2 × 7500 = 7500e0.143t:
2 = e0.143t
⌊ ln(2) / 0.143 ⌋ ≈ t
t ≈ ⌊ ln(2) / 0.143 ⌋
t ≈ 4.85 years
This process demonstrates the power of compound interest and its impact on investments over time.