Three groups of students collect tree species, the ratio of work efficiency of Group A, Group B, and Group C is 5:3:4. Group A collected 15 kilograms, how much less was collected in Group B than in Group C?
三组同学采集树种，甲组、乙组、丙组的工作效率的比是5：3：4．甲组采集了15千克，乙组比丙组少采集多少千克？
<gadget id="calculator">5 + 3 + 4</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">15 / (5/12)</gadget>
<output>36</output>

<gadget id="calculator">4 / 12</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">36 * (1/3)</gadget>
<output>12</output>

<gadget id="calculator">3 / 12</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">36 * (1/4)</gadget>
<output>9</output>

<gadget id="calculator">12 - 9</gadget>
<output>3</output>

<result>3</result>