If 80% of the people in a company are proficient in English and 50% are proficient in French, at least how many people in this company are proficient in French.
某公司有80%的人精通英语，50%的人精通法语，这家公司精通法语的人中至少有多少的人精通法语．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) - 1</gadget>
<output>-1/2 = around -0.5</output>

<gadget id="calculator">(4/5) + (-1/2)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/10) / (1/2)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>