Xiao Ming went to the store to buy 66 red and black pens in total. Each red pen is priced at 5 yuan, and each black pen is priced at 9 yuan. Because the quantity bought is large, the store will give a discount, the red pen will be paid at 85% of the price, and the black pen will be paid at 80% of the price. If he pays 18% less than the price, then he bought the red pen How many sticks?
小明到商店买红、黑两种笔共66支．红笔每支定价5元，黑笔每支定价9元．由于买的数量较多，商店就给予优惠，红笔按定价85%付钱，黑笔按定价80%付钱，如果他付的钱比按定价少付了18%，那么他买了红笔多少支？
<gadget id="calculator">5 + 6</gadget>
<output>11</output>

<gadget id="calculator">6 / 11</gadget>
<output>6/11 = around 0.545455</output>

<gadget id="calculator">66 * (6/11)</gadget>
<output>36</output>

<result>36</result>