Group A and Group B manufacture the same machine at the same time. 10 people in group A made 3 machines, and 15 people in group B made 4 machines. Which group is more efficient? How high is it?
甲、乙两个组在同一时间内制造同一种机器．甲组10人制造了3台机器，乙组15人制造了4台机器，哪个组工作效率高？高多少？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">4 / 15</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">(3/10) - (4/15)</gadget>
<output>1/30 = around 0.033333</output>

<result>1/30 = around 0.033333</result>