Solve for the unknown number of years in each of the following:

Note: Do not round intermediate calculations and round your answers to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

$\backslash$table$[[$Present Value,Years,Interest Rate,,Future Value$],[600,,11,\%,1,455],[2,291,,9,\%,4,050],[33,505,,14,\%,390,620],[33,200,,21,\%,208,796]]$