Answer: number of years that it will take for the balance to reach $120,000 is 42 years
Step-by-step explanation:
Initial amount deposited into the account is $4000. This means that the principal is $4000
P = 4000
It was compounded annually. This means that it was compounded once in a year. So
n = 1
The rate at which the principal was compounded is 8.4%. So
r = 8.4/100 = 0.084
Let the number of years that it will take for the balance to reach $120,000. It means that it was compounded for a total of t years.
Amount, A at the end of t years is $120,000
The formula for compound interest is
A = P(1+r/n)^nt
120000 = 4000(1 + 0.084/1)^1×t
120000/4000 = 1.084^t
30 = 1.084^t
t = 42 years
