Xinhua Bookstore held a three-day discount book sale event. The books sold on the first day accounted for 3/8 of the total, and the second day sold 200 fewer books than the first day. The number of books sold on the third day and the second day The ratio is 4:1, how many books were sold in these three days?
新华书店举行三天优惠卖书活动，第一天卖出的书占总数的(3/8)，第二天比第一天少卖200本书，第三天和第二天卖出的本数之比是4：1，这三天共卖出多少本书？
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">1 - (3/8)</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(5/8) * (1/5)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(3/8) - (1/8)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">200 / (1/4)</gadget>
<output>800</output>

<result>800</result>