How long does it take an investment to quadruple in value if it earns 5% simple interest per year?
I'm not sure about how to find it but the Awnser: 60 years
How long does it take an investment to quadruple in value if it earns 5% simple interest per year?
I'm not sure about how to find it but the Awnser: 60 years
Say the investment amount is $P$ and takes $\color{blue}{T}$ years to grow to $4P$ :
$$P + P*0.05*\color{blue}{T} = 4P$$
Divide $P$ through out and get $$1 + 0.05*\color{blue}{T} = 4$$
See if you can take it home from here..