Answer:
The investment in 42 years will become $115199.88
Step-by-step explanation:
Let the investment model is [tex]A=Pe^{rt}[/tex]
A = final amount
P = initial amount
r = rate
t = time
Now, given that
P = $1800
A = 2P = 2×1800 = $3600
t = 7 years
[tex]3600=1800e^{7r}\\\\2=e^{7r}\\ln2=7r\\r=\frac{1}{7}\ln2\\\\r=0.099021[/tex]
Now, we have to find A for t = 42 years
[tex]A=1800e^{42\times0.099021}\\\\A=115199.88[/tex]
Hence, the investment in 42 years will become $115199.88