factory produces a batch of cement. The original plan is to produce 150 tons per day, and the task can be completed in 20 days. The actual daily production is increased (1/3) compared with the original plan, how many days can the actual use be reduced? (Solve with ratio)
某厂生产一批水泥，原计划每天生产150吨，20天可以完成任务．实际每天比原计划增产(1/3)，实际可以少用几天？(用比例解)
<gadget id="calculator">150 * 20</gadget>
<output>3_000</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 + (1/3)</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">150 * (4/3)</gadget>
<output>200</output>

<gadget id="calculator">3_000 / 200</gadget>
<output>15</output>

<gadget id="calculator">20 - 15</gadget>
<output>5</output>

<result>5</result>