You invest $200 at 4% compounded annually. How many years would it take for the $200 to double in value?

Question

anonymous · Answer

@Luigi0210

anonymous · Answer

help help help !!! @surjithayer

anonymous · Answer

help me get the answer

anonymous · Answer

$$400=200\left( 1+\frac{ 4 }{ 100 } \right)^{n}$$
$$\frac{ 400 }{ 200 }=\left( \frac{ 26 }{ 25 } \right)^{n},2=\left( \frac{ 26 }{ 25 }\right)^{n}$$
taking log of both sides and solve.

anonymous · Answer

how do I take log from both side and solve ? Im really confused .. can you just show me the whole step?

anonymous · Answer

log1.04( 200-1.04) ???

anonymous · Answer

$$\log \left( \frac{ 26 }{ 25 } \right)^{n}=\log2,n \left( \log26-\log25 \right)=\log2,n=\frac{ \log 2 }{ \log26-\log25 }$$

anonymous · Answer

the answer is ..17.67???

anonymous · Answer

now you can solve by taking log

anonymous · Answer

answer ^^^^

anonymous · Answer

17.67?

anonymous · Answer

i have no log table or calculator. you can solve.

anonymous · Answer

try this http://www.wolframalpha.com/input/?i=log+fit+calculator

anonymous · Answer

I want you to check if it's right

anonymous · Answer

@surjithayer

anonymous · Answer

is it 18 years ?????@surjithayer

anonymous · Answer

$$n=\frac{ .6931 }{ 3.2580-3.2189}=17.67$$

anonymous · Answer

ok thanks

anonymous · Answer

yw