A factory used 550 tons of water in October, which was 1/10 more than the original plan. How many tons of water was originally planned for October?
某工厂十月份用水550吨，比原计划多用了(1/10)，十月份原计划用水多少吨？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

<gadget id="calculator">550 / (11/10)</gadget>
<output>500</output>

<result>500</result>