There are three interest groups: art, music, and calligraphy. The number of people in art accounts for 4/15 of the total number of people. There are 12 more people in music than art. Music: art = 6:5. How many people are there in total?
有美术、音乐、书法三个兴趣小组，美术人数占总人数的(4/15)，音乐比美术多12人，音乐：美术=6：5，求一共多少人？
<gadget id="calculator">6 - 5</gadget>
<output>1</output>

<gadget id="calculator">12 / 1</gadget>
<output>12</output>

<gadget id="calculator">4 / 15</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">5 / (4/15)</gadget>
<output>75/4 = around 18.75</output>

<gadget id="calculator">12 * (75/4)</gadget>
<output>225</output>

<result>225</result>