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$],[$$$,12,\%,$$$,1,755],[900,,10,\%,4,350],[2,591,,15,\%,393,620],[34,105,,22,\%,217,868],[33,800,,,,]]$