Xiaohua participated in a mathematics competition, and there were 10 questions in total. Ten points are awarded for each correct answer, and five points are deducted for each incorrect answer. Xiaohua answered all ten questions and scored 85 points. How many questions did Xiaohua answer correctly?
小华参加数学竞赛，共有10道赛题．规定答对一题给十分，答错一题扣五分．小华十题全部答完，得了85分．小华答对了多少题．
<gadget id="calculator">10 * 10</gadget>
<output>100</output>

<gadget id="calculator">100 - 85</gadget>
<output>15</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

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

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<result>9</result>