The green workers have to plant 240 trees, with an average of 50 trees per day. After a few days, there are still (1/6) left unplanted. How many days have the green workers planted?
绿化工人要栽240棵树，平均每天栽50棵，若干天后，还剩(1/6)没有栽，绿化工人已经栽了多少天？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/6)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) / 50</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">240 * (1/60)</gadget>
<output>4</output>

<result>4</result>