Problema Solution
how long (in years and months) will it take for and investment to double at 5% compounded monthly?
Answer provided by our tutors
let t=time in months __ a=2p (doubling) __ r=.05
a=p(1+(r/12))^t _
dividing by p
2=(1+(.05/12)^t
taking log
log(2)=t*log(1+(.05/12)
dividing by log(1+(.05/12) __ [log(2)]/[log(1+(.05/12)]=t
t=166.7 (approx) __ should be 167 to get final compounding