A piece of land can be plowed by tractor A in 15 hours, tractor B can be plowed in 10 hours, and both tractors can be plowed in 2 hours at the same time. How many hours will it take for A to plow the rest?
一块地，甲拖拉机15小时能耕完，乙拖拉机10小时能耕完，两拖拉机同时耕2小时，剩下的甲耕，还要几小时耕完？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/15) + (1/10)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/6) * 2</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) / (1/15)</gadget>
<output>10</output>

<result>10</result>