36+(40+△)/[1-(1-1/3)x60%]=216
(40+△)/[1-(2/3)x60%]=216-36
(40+△)/[1-40%]=180
(40+△)/60%=180
40+△=60%x180
△=108-40=68验算后不对啊。。验算：
左式=36+(40+68)/[1-(1-1/3)x60%]
=36+(108)/[1-(2/3)x60%]
=36+(108)/[1-40%]
=36+108/60%
=36+180
=216
=右式哦，谢谢。我先加36加108了好评...