Answer: it will take 13.3 years
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 = 6000
A = 10000
r = 4% = 4/100 = 0.04
n = 12 because it was compounded 12 times in a year.
Therefore,.
10000 = 6000(1 + 0.04/12)^12 × t
10000/6000(1 + 0.0033)^12t
1.67 = 1.0033^12t
Taking log to base 10 of both sides, it becomes
Log 1.67 = 12tLog 1.0033
0.223 = 12t × 0.0014
0.223 = 0.0168t
t = 0.223/0.0168
t = 13.3 years