Answer: it will take 36 years for the account balance to reach $1,200.
Step-by-step explanation:
We would apply the formula for determining compound interest which is expressed as
A = P(1+r/n)^nt
Where
A = total amount in the account at the end of t years
r represents the interest rate.
n represents the periodic interval at which it was compounded.
P represents the principal or initial amount deposited
From the information given,
P = 70
A = 1200
r = 1.5% = 1.5/100 = 0.015
n = 1 because it was compounded once in a year.
Therefore,.
1200 = 700(1 + 0.015/1)^1 × t
1200/700 = (1.015)^t
1.714 = 1.015^t
Taking log of both sides,
Log 1.714 = log 1.015^t
0.234 = tlog 1.015 = t × 0.0065
t = 0.234/0.0065
t = 36 years
