There are 650 three kinds of fruit trees in the orchard, apple trees are 3 times that of pear trees, peach trees are 1.2 times of pear trees, how many pear trees are there?
果园里有三种果树共650棵，苹果树是梨树的3倍，桃树是梨树的1.2倍，梨树有多少棵？
<result>15</result>