When Arbor Day comes, the students in Class 8 planted 6 trees, and every two trees are 2 meters apart. According to this calculation, how many meters is the distance between planting 15 trees?
植树节到了的时候，八班的学生栽了6棵树，每两棵间隔2米，照这样计算，栽15棵树距离是多少米﹖
<gadget id="calculator">15 - 1</gadget>
<output>14</output>

<gadget id="calculator">14 * 2</gadget>
<output>28</output>

<result>28</result>