It will take about 5 years for her investment to grow to $2400.
The formula for calculating the compound amount is expressed according to the equation;
[tex]A=P(1+\frac{r}{n} )^{nt}[/tex]
Substitute the given parameters into the formula to have:
[tex]2400=1600(1+\frac{0.08}{12} )^{12t}\\1.5=(1+0.00667)^{12t}\\[/tex]
Take the natural logarithm of both sides
[tex]ln(1.5)=12tln(1.00667)\\12t=\frac{ln(1.5)}{ln(1.00667)}\\t = \frac{0.4054}{0.07977}\\t= 5.082years[/tex]
Hence it will take about 5 years for her investment to grow to $2400
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