Problem $5-5$ Calculating the Number of Periods $[$LO$4]$

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$],[$$$,9,\%,$$$,1,212],[510,,10,\%,1,629],[760,,17,\%,260,563],[17,900,,15,\%,391,887],[21,000,,,,]]$