There are 15 pagoda trees in the school. The number of poplar trees is 1/3 of pagoda trees and 1/4 of willow trees. How many poplar trees, pagoda trees, and willow trees are there in the school?
学校有槐树15棵，杨树的棵数是槐树的(1/3)，又是柳树的(1/4)，学校里杨树、槐树、柳树共有多少棵？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">15 * (1/3)</gadget>
<output>5</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">5 / (1/4)</gadget>
<output>20</output>

<gadget id="calculator">5 + 20 + 15</gadget>
<output>40</output>

<result>40</result>