Zhang San bought a total of 30 two kinds of theater tickets, paid 200 yuan, and got back 5 yuan. Each type A ticket is 7 yuan, and each type B ticket is 6 yuan. How many Type A tickets did Zhang San buy?
张三买了两种戏票一共30张，付出200元，找回5元．甲种票每张7元，乙种票每张6元．张三买了多少张甲种票？
<gadget id="calculator">30 * 6</gadget>
<output>180</output>

<gadget id="calculator">200 - 5 - 180</gadget>
<output>15</output>

<gadget id="calculator">7 - 6</gadget>
<output>1</output>

<gadget id="calculator">15 / 1</gadget>
<output>15</output>

<result>15</result>