There are 45 students in the basketball team and the track and field team of our school. When a student transfers from the track and field team to the basketball team, the ratio of the track and field team to the basketball team is 4:5. How many people are there in the track and field team?
我校篮球队与田径队共有学生45人，当有1名学生从田径队转入篮球队后，田径队与篮球队人数之比为4：5，田径队原有多少人．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) * 45</gadget>
<output>36</output>

<gadget id="calculator">1 + 36 + (4/5)</gadget>
<output>189/5 = around 37.8</output>

<gadget id="calculator">1 + (4/5)</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">(189/5) / (9/5)</gadget>
<output>21</output>

<result>21</result>