A and B work together to complete 105 machine parts. It takes 3 minutes for A to make one part, and 4 minutes for B to make one part. When this batch of parts is completed, how many parts does A make?
甲、乙二人共同完成105个机器零件，甲做一个零件要3分钟，乙做一个零件要4分钟，完成这批零件时，甲做了的零件个数为多少
<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">105 * (4/7)</gadget>
<output>60</output>

<result>60</result>