There are 20 rows of peach trees in an orchard, and each row has the same number of trees. If the same 5 rows are planted again, 120 more trees will be added than before. How many peach trees were there in the orchard?
果园里有20行桃树，每行棵树相等．如果再栽同样的5行就比原来增加了120棵．果园里原来有桃树多少棵？
<gadget id="calculator">120 / 5</gadget>
<output>24</output>

<gadget id="calculator">24 * 20</gadget>
<output>480</output>

<result>480</result>