Last year, our school used 150 tons of coal for heating, saving (1/6) compared with the previous year. How many tons of coal was used in the previous year?
我校去年取暖用煤150吨，比前年节约(1/6)，前年用煤多少吨？
<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">150 / (5/6)</gadget>
<output>180</output>

<result>180</result>