Xinxing Flour Factory produces a batch of flour. The original plan is to produce 3.2 tons per day and the task can be completed on time. The actual daily production was 1.6 tons more than the original plan, and the task was completed in only 10 days. How many days before the original plan was the actual completion of the task?
新星面粉厂生产一批面粉，原计划每天生产3.2吨可按时完成任务．实际每天比原计划多生产1.6吨，只用10天就完成了任务．实际比原计划提前几天完成了任务？
<gadget id="calculator">3.2 + 1.6</gadget>
<output>4.8</output>

<gadget id="calculator">10 / 3.2</gadget>
<output>3.125</output>

<gadget id="calculator">4.8 * 3.125</gadget>
<output>15</output>

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

<result>5</result>