8.果园里有梨树、桃树和苹果树共有366棵.梨树棵数比桃树少15%,苹果树棵数比桃树多20%,果园里有桃树多少棵?

设梨树x棵,桃树y棵,苹果树z棵.可得x+y+z=366,x=(1-0.15)y,z=(1+0.2)y,解得y=12