350 boxes of water bottle refills, 6 pieces per box. The contract stipulates that the shipping fee for each box is 10 yuan. If a box is damaged, no shipping fee will be paid and 50 yuan will be compensated for the loss. At the time of settlement, the shipping fee was 3,200 yuan. How many water bottle bladders were damaged? (can be answered step by step)
托运水瓶胆350箱，每箱装6个．合同规定每箱运费10元，如果损坏一箱，不给运费并赔偿损失50元．结算时，共得运费3200元，一共损坏了多少个水瓶胆？(可以分步解答)
<gadget id="calculator">350 * 10</gadget>
<output>3_500</output>

<gadget id="calculator">3_500 - 3_200</gadget>
<output>300</output>

<gadget id="calculator">50 + 10</gadget>
<output>60</output>

<gadget id="calculator">300 / 60</gadget>
<output>5</output>

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

<result>30</result>