Mr. Zhang ordered 84 pieces of a certain product priced at 100 yuan each from the store. Mr. Zhang said to the store manager: "If you are willing to reduce the price, then for every 1 yuan price reduction, I will order 4 more pieces." The store manager calculated that if the price was reduced by 4%, Mr. Zhang’s profit would be 32 yuan more than the original one because he ordered more. Q: How much does this commodity cost?
张先生向商店订购了每件定价100元的某中商品84件，张先生对商店经理说："如果你肯减价，那么每减价1元，我就多订购4件"．商店经理算了一下，若减价4%，则由于张先生多订购，获得的利润反而比原来多32元．问：这种商品的成本是多少元？
<gadget id="calculator">4 / 100</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">100 * (1/25)</gadget>
<output>4</output>

<gadget id="calculator">100 - 4</gadget>
<output>96</output>

<gadget id="calculator">96 * 84</gadget>
<output>8_064</output>

<gadget id="calculator">96 * 100 * (1/25) * 4</gadget>
<output>1_536</output>

<gadget id="calculator">100 * 84</gadget>
<output>8_400</output>

<gadget id="calculator">1_536 - 8_400 - 32</gadget>
<output>-6_896</output>

<gadget id="calculator">8_064 + (-6_896)</gadget>
<output>1_168</output>

<gadget id="calculator">100 * (1/25) * 4</gadget>
<output>16</output>

<gadget id="calculator">16 - 84</gadget>
<output>-68</output>

<gadget id="calculator">84 + (-68)</gadget>
<output>16</output>

<gadget id="calculator">1_168 / 16</gadget>
<output>73</output>

<result>73</result>