The water price for residents in a certain city is as follows: the part of each household that does not exceed 5 tons per month is charged at 4 yuan per ton, the part that exceeds 5 tons and does not exceed 10 tons is charged at 6 yuan per ton, and the part that exceeds 10 tons is charged at 8 yuan per ton If a household pays a total of 108 yuan for water in one month, how many tons is the total amount of water used by the residents of this household this month?
某城市居民用水价格为：每户每月不超过5吨的部分按照每吨4元收取，超过5吨不超过10吨的部分按每吨6元收取，超过10吨的部分按每吨8元收取，某户一个月共交水费108元，则该户居民这个月用水总量为多少吨？
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">10 - 5</gadget>
<output>5</output>

<gadget id="calculator">6 * 5</gadget>
<output>30</output>

<gadget id="calculator">20 + 30</gadget>
<output>50</output>

<gadget id="calculator">108 - 50</gadget>
<output>58</output>

<gadget id="calculator">58 / 8</gadget>
<output>29/4 = around 7.25</output>

<gadget id="calculator">(29/4) + 10</gadget>
<output>69/4 = around 17.25</output>

<result>69/4 = around 17.25</result>