It is planned that 15 people can move a pile of bricks in 4 hours. After 2 hours of actual work, 5 people will be transferred away. How many hours will it take to move the remaining bricks?
搬一堆砖，计划15人4小时可以搬完，实际劳动2小时后有5人被调走，余下的砖还需多少小时搬完．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) * 2</gadget>
<output>1/2 = around 0.5</output>

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

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

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

<gadget id="calculator">(1/15) * (1/4) * 10</gadget>
<output>1/6 = around 0.166667</output>

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

<result>3</result>