Gymnastics and tug-of-war competitions are held in the sixth grade, and the number of participants accounts for 40% of the whole grade. Those who participated in gymnastics competition accounted for (2/5) of the total number of participants, those who participated in tug-of-war competition accounted for (3/4) of the total number of participants, and 12 people participated in both. How many people are there in the whole grade?
六年级举行体操和拔河比赛，参加人数占全年级人数的40%．参加体操比赛的占参加总人数的(2/5)，参加拔河比赛的占参加总人数的(3/4)，两项都参加的有12人．全年级有多少人？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) - 1</gadget>
<output>-1/4 = around -0.25</output>

<gadget id="calculator">(2/5) + (-1/4)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">12 / (3/20) / (2/5)</gadget>
<output>200</output>

<result>200</result>