Final answer:
Hector waited approximately 2.935 years for his bank balance to increase from $150 to $168.73 at an annual interest rate of 4% when compounded annually.
Step-by-step explanation:
To determine how long Hector needed to wait for his balance to increase from $150 to $168.73 with an annual interest rate of 4%, we will use the formula for compound interest which is A = P(1 + r/n)(nt), where:
A is the amount of money accumulated after n years, including interest.
P is the principal amount.
r is the annual interest rate (decimal).
n is the number of times that interest is compounded per year.
t is the time the money is invested for in years.
Since the compounding frequency is not mentioned, we'll assume it is compounded once a year (n=1). We need to solve for t given:
P = $150
r = 0.04 (4% written in decimal form)
A = $168.73
The equation thus becomes $168.73 = $150(1 + 0.04)t.
To solve for t, we will first divide both sides of the equation by $150 to isolate the growth factor:
$168.73 / $150 = (1 + 0.04)t
Now solving for t, we'll use logarithms:
t = log(168.73/150) / log(1.04)
Using a calculator to find the value of t gives:
t ≈ 2.935
Therefore, Hector waited approximately 2.935 years to check his balance.