If 20% of students who participate in dance from class VI also participate in play then find the ratio of students from class VI who participated only in Dance to students participated only in play.

Students who participate only in dance from class VI

$= frac{{15}}{{100}} imes 500 - frac{{20}}{{100}} imes frac{{15}}{{100}} imes 500$

$= 75 - frac{1}{5} imes 75 = 60$

Students who participate only in play from class VI

$= frac{8}{{100}} imes 500 - 15 = 40 - 15 = 25$

Required ratio = 60 : 25 = 12 : 5