The original number of boys in the interest group was the number of girls (5/6). Later, 2 boys joined in. At this time, the ratio of the number of girls to the number of boys was 8:7. How many boys were there in the interest group?
兴趣小组原有男生人数是女生人数的(5/6)，后来后来又来了2名男生参加，这时女生人数与男生人数的比是8：7，兴趣小组原有男生多少人？
<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(7/8) - (5/6)</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">2 / (1/24)</gadget>
<output>48</output>

<gadget id="calculator">48 * (5/6)</gadget>
<output>40</output>

<result>40</result>