In order to train students to develop the habit of caring for the environment from an early age, the school organizes three classes in the sixth grade to collect used batteries. The first class collected 120 yuan. The ratio of the number of used batteries collected by the first class and the second class was 2:3. The number collected by the third class accounted for 40% of the total collection of the sixth grade. How many used batteries were collected by the sixth grade?
为了培养同学们从小养成爱护环境的习惯，学校组织六年级的三个班收集废旧电池．一班收集了120块，一班和二班收集废旧电池数的比是2：3，三班收集的数量占六年级收集总数的40%，六年级一共收集多少块废旧电池？
<gadget id="calculator">120 / 2</gadget>
<output>60</output>

<gadget id="calculator">60 * 3</gadget>
<output>180</output>

<gadget id="calculator">180 + 120</gadget>
<output>300</output>

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

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">300 / (3/5)</gadget>
<output>500</output>

<result>500</result>