If A and B work together on a project for 5 hours, they can complete half of the project. A alone takes half as much time as the two. How many days does B need to do the project alone?
一项工程甲、乙两人合作5小时，可以完成工程的一半，甲单独需的时间比两人合作需的多一半，乙单独做这项工程需多少天？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) / 5</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) - (1/15)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / (1/30)</gadget>
<output>30</output>

<result>30</result>