There are 120 students in the third grade of a certain elementary school, and the test scores have reached excellent (9/10). And (4/5) of the outstanding students are girls, what percentage of the total number of students in the third grade are the boys who have reached the excellence?
某小学三年级有120人，考试成绩已经达到优秀的占(9/10)．而达到优秀学生的(4/5)是女生，男生达到优秀的学生占三年级总人数的几分之几？
<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

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

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(9/10) * (1/5)</gadget>
<output>9/50 = around 0.18</output>

<result>9/50 = around 0.18</result>