Solve for the unknown number of years in each of the following: $($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$],[$$$,500,8,\%,$$$,1,075],[1,750,,12,\%,,1,836],[,17,800,,18,\%,,294,671],[,20,900,,14,\%,,320,610]]$