There are 16 apple trees in a row, and the distance between two adjacent trees is 3 meters. There is a well next to the first tree. Xiao Ming uses a bucket to water the apple trees. How many meters did Xiao Ming walk for one tree?
一行苹果树有16棵，相邻两棵间的距离都是3米，在第一棵树旁有一口水井，小明用1只水桶给苹果树浇水，每棵浇半桶水，浇完最后一棵时，小明共走了多少米．
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">7 * 12</gadget>
<output>84</output>

<gadget id="calculator">6 + 84</gadget>
<output>90</output>

<gadget id="calculator">6 + 90</gadget>
<output>96</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">96 * 4</gadget>
<output>384</output>

<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<gadget id="calculator">384 - 45</gadget>
<output>339</output>

<result>339</result>