What is the average of students who participating in Play from all class.

Required average

= $frac{{frac{8}{{100}} imes 500 + frac{6}{{100}} imes 400 + frac{{10}}{{100}} imes 360 + frac{{12}}{{100}} imes 250}}{4}$

$= frac{{130}}{4} = frac{{65}}{2} = 32frac{1}{2}$