The school saved (1/7) more water in October than in September, and 8 tons more water in September than in October. How many tons of water was used in September?
学校十月份比九月份节约了(1/7)，九月份比十月份多用水8吨，九月份用水多少吨？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">8 / (1/7)</gadget>
<output>56</output>

<result>56</result>