A street plans to install a batch of street lamps, 250 lamps have been installed, and there are still (6/11) not installed, how many lamps are there in this batch?
一条街道计划安装一批路灯，安装了250盏，还有(6/11)没有安装，这批路灯共有多少盏？
<gadget id="calculator">6 / 11</gadget>
<output>6/11 = around 0.545455</output>

<gadget id="calculator">1 - (6/11)</gadget>
<output>5/11 = around 0.454545</output>

<gadget id="calculator">250 / (5/11)</gadget>
<output>550</output>

<result>550</result>