Only (3/4) of the seats in a long-distance bus are filled with passengers. 4 people get off at a certain station, and 6 people get on again. At this time, the ratio of the number of seats in the car to the number of empty seats is 4:1. How many seats does this car have?
一辆长途客车只有(3/4)的座位坐了乘客．途经某站下车4人，又上来了6人，此时车上已坐的座位和空座位的数量之比是4：1，这辆车共有多少个座位？
<gadget id="calculator">6 - 4</gadget>
<output>2</output>

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

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(4/5) - (3/4)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">2 / (1/20)</gadget>
<output>40</output>

<result>40</result>