There are 8 unqualified parts in a batch, at least how many qualified parts are required to ensure a pass rate of 98%
一批零件有8个不合格，至少要有多少个合格，才能保证合格率98%
<gadget id="calculator">98 / 100</gadget>
<output>49/50 = around 0.98</output>

<gadget id="calculator">1 - (49/50)</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">8 / (1/50)</gadget>
<output>400</output>

<gadget id="calculator">400 - 8</gadget>
<output>392</output>

<result>392</result>