The following data give the weights $($in pounds$)$ lost by $15$ members of a health club at the end of two months after joining the club.

$\backslash$table$[[5,10,8,7,25,12,5,13,11,10],[21,9,8,11,13,,,,,]]$

$($a$)$ Calculate the approximate value of the ${82}^{nd}$ percentile, denoted $P_{82}.$

$P_{82}=$

$($b$)$ Find the percentile rank of $10.$

Give the answer rounded to the nearest percent.

The percentile rank of $10=\%$