It is necessary to plant some willows equidistantly around a pond with a length of 400 meters, with a distance of 8 meters, and then plant 3 poplars between every two willows. How many trees are planted around the pond?
要在一周长400米的池塘周围等距离地栽一些柳树，株距8米，再在每两棵柳树间栽3棵杨树，这个池塘周围一共栽树多少棵．
<gadget id="calculator">400 / 8</gadget>
<output>50</output>

<gadget id="calculator">50 * 3</gadget>
<output>150</output>

<gadget id="calculator">50 + 150</gadget>
<output>200</output>

<result>200</result>