Answer: [tex]6.12\ \text{years}[/tex]
Step-by-step explanation:
Given
Rate of interest is [tex]r=3\%[/tex] compounded quarterly
So, annually it is [tex]r=12\%[/tex]
Suppose [tex]P[/tex] is the Principal and A is the amount after certain time period.
Amount in Compound interest is given by
[tex]\Rightarrow A=P[1+r\%]^t[/tex]
for given conditions
[tex]\Rightarrow 2P=P[1+0.12]^t\\\Rightarrow 2=(1.12)^t\\\\\Rightarrow t=\dfrac{\ln (2)}{\ln (1.12)}\\\\\Rightarrow t=6.116\approx 6.12\ \text{years}[/tex]
It take [tex]6.12\ \text{years}[/tex] to double the invested amount.
