Xiaoqiang goes to the store to buy two kinds of whiteboard markers, red and blue. The price of red whiteboard markers is 5 yuan, and the price of blue whiteboard markers is 9 yuan. Since the quantity bought is relatively large, the store will give a discount. The red whiteboard markers are sold at 85% of the price, and the blue ones The white board marker was sold at 80% of the price, so he paid 18% less. It is known that he bought 30 blue whiteboard markers, so how many red whiteboard markers did he buy?
小强到商店买红、蓝两种白板笔，红色白板笔定价5元，蓝色白板笔定价9元，由于买的数量比较多，商店就给打折扣，红色白板笔按定价的85%出售，蓝色白板笔按定价的80%的出售，结果他付的钱就少了18%．已知他买了30支蓝色的白板笔，那么他买了多少支红色的白板笔．
<gadget id="calculator">30 * 9</gadget>
<output>270</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">9 * 30 * (4/5)</gadget>
<output>216</output>

<gadget id="calculator">18 / 100</gadget>
<output>9/50 = around 0.18</output>

<gadget id="calculator">30 * 9 * (9/50)</gadget>
<output>243/5 = around 48.6</output>

<gadget id="calculator">270 - 216 - (243/5)</gadget>
<output>27/5 = around 5.4</output>

<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">5 * (17/20)</gadget>
<output>17/4 = around 4.25</output>

<gadget id="calculator">5 * (9/50)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">(9/10) - 5</gadget>
<output>-41/10 = around -4.1</output>

<gadget id="calculator">(17/4) + (-41/10)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(27/5) / (3/20)</gadget>
<output>36</output>

<result>36</result>