There are 150 peach trees in the orchard, 10 more apple trees than peach trees, and 20 fewer than three times the number of pear trees. How many pear trees are there?
果园里有桃树150棵，苹果树比桃树多10棵，比梨树的3倍少20棵，梨树有多少棵？
<gadget id="calculator">150 + 10 + 20</gadget>
<output>180</output>

<gadget id="calculator">180 / 3</gadget>
<output>60</output>

<result>60</result>