Question 252472
We want our money to double. P = principal, A = 2*principal = 2P. r = 5.5% or 0.055. So, we have 
{{{A = Pe^rt}}}
{{{2P = Pe^0.055*t}}}
canceling the P and taking a natural log "LN" of both sides, we get
{{{ln(2) = .055t}}}
solving for t, we get
t ~ 12.60 years to the nearest hundredth of a year.
t ~ 12 years 220 days to the nearest tenth.