How long will it take for an investment to double at 7% p.a compounded monthly?
i = .07/12 = .0058333...
n = ?
1(1.005833..)^n = 2
log both sides
n log 1.005833.. = log 2
n = log 2/log 1.0058333... = 119.17.. months
= appr 9 years and 11 months