In the fifth grade of Guangming Primary School, 250 students participated in the interest activity group, among which (1/5) participated in the mathematics Olympiad group, and (3/10) participated in the art group. Q: What percentage of the fifth grade students take part in the mathematics Olympiad group and the art group?
光明小学五年级有学生250人参加兴趣活动组，参加数学奥赛组的占(1/5)，美术组的占(3/10)．问参加数学奥赛组和美术组的学生共占五年级人数的几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(1/5) + (3/10)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>