Principal amount deposited in a savings account = $150
Final amount of money needed = $3000
Percentage of interest = 2.5%
Let us assume the time taken = t years
Then
A = P (1 + r/n) ^ nt
3000 = 150(1 +0.025/12)^t
3000 = 150 (1 + 0.002083)^t
(1.002083)^t = 20
Taking log on both sides we get
log (1.002083)^t = log 20
t ln(1.002083) = ln(20)
t = ln(20)/ln(1.002083)
= 1439.68
= 119.973 years
From the above deduction we can easily conclude that the correct option among all the options that are given in the question is the second option or option "B".
