The supermarket is promoting a sale. Buying one piece of soap costs 3.6 yuan, buying 3 pieces of soap only costs 8.7 yuan; buying 5 pieces of soap only charges 14 yuan;
超市为促销，肥皂买一块收3.6元，买3块只收8.7元；买5块只收14元；买16块至少要付多少元．
<gadget id="calculator">14 * 2</gadget>
<output>28</output>

<gadget id="calculator">8.7 * 2</gadget>
<output>17.4</output>

<gadget id="calculator">28 + 17.4</gadget>
<output>45.4</output>

<result>45.4</result>