Answer:
1: the balance after 8 years is approximately $151.78.
2: is approximately 7%.
Explanation:
1: The balance after t years with continuous compounding can be calculated using the formula:
B = Pe^(rt)
Where:
P = 120 dollars (initial deposit)
r = 2.5% = 0.025 (interest rate in decimal form)
t = 8 years
Substituting these values into the formula, we get:
B = 120e^(0.025*8) ≈ 151.78
Therefore, the balance after 8 years is approximately $151.78.
2: The interest rate can be found using the formula:
A = Pe^(rt)
Taking the natural logarithm of both sides and solving for r, we get:
r = ln(A/P) / t
Where:
A = 4055 dollars (final amount)
P = 1000 dollars (initial investment)
t = 20 years
Substituting these values into the formula, we get:
r = ln(4055/1000) / 20 ≈ 0.0774
Converting to a percentage and rounding to the nearest whole number, we get:
r ≈ 7%
Therefore, the interest rate, if compounded continuously, is approximately 7%.