Among the students participating in physical exercise on the playground, after 15 girls left, the number of boys was twice that of girls, and then 45 boys left, and the number of girls was five times that of boys. How many people participated in the exercise? people.
操场上参加体育锻炼的学生中，女生走了15人后，男生人数是女生的2倍，后来又走了45名男生，这时女生人数是男生的5倍，原来参加的锻炼的一共有多少人．
<gadget id="calculator">2 * 15</gadget>
<output>30</output>

<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<gadget id="calculator">45 - 3</gadget>
<output>42</output>

<gadget id="calculator">30 + 42</gadget>
<output>72</output>

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

<gadget id="calculator">2 - (1/5)</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">72 / (9/5)</gadget>
<output>40</output>

<gadget id="calculator">40 - 15</gadget>
<output>25</output>

<gadget id="calculator">2 * 25</gadget>
<output>50</output>

<gadget id="calculator">40 + 50</gadget>
<output>90</output>

<result>90</result>