Answer: 6.93 years
Step-by-step explanation:
Given
Rate of interest is ![r=10\%](https://tex.z-dn.net/?f=r%3D10%5C%25)
Future value is given by ![s=1000e^{0.1t}](https://tex.z-dn.net/?f=s%3D1000e%5E%7B0.1t%7D)
For the investment to double itself, i.e. ![s=2000](https://tex.z-dn.net/?f=s%3D2000)
![\Rightarrow 2000=1000e^{0.1t}\\\Rightarrow 2=e^{0.1t}\\\\\text{Taking log both sides}\\\\\Rightarrow \ln 2=0.1t\\\\\Rightarrow t=\dfrac{\ln 2}{0.1}\\\\\Rightarrow t=6.93\ \text{years}](https://tex.z-dn.net/?f=%5CRightarrow%202000%3D1000e%5E%7B0.1t%7D%5C%5C%5CRightarrow%202%3De%5E%7B0.1t%7D%5C%5C%5C%5C%5Ctext%7BTaking%20log%20both%20sides%7D%5C%5C%5C%5C%5CRightarrow%20%5Cln%202%3D0.1t%5C%5C%5C%5C%5CRightarrow%20t%3D%5Cdfrac%7B%5Cln%202%7D%7B0.1%7D%5C%5C%5C%5C%5CRightarrow%20t%3D6.93%5C%20%5Ctext%7Byears%7D)
It takes around 6.93 years to double the investment.
the answer is A couse divide all 5
The number is increasing by 2 every time.
78 x 2 = 156
-4 + 156 = 152
The 78th term is 152