The ratio of people in workshop A and B is 3:5. If workshop B transfers 10 people, the ratio of people in workshop A and B is now 4:7. How many people were there in workshop A?
甲乙两车间人数比是3：5，若乙车间调进10人，现在甲乙车间的人数比是4：7，原来甲车间有多少人？
<gadget id="calculator">7 / 4</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">5 / 3</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">(7/4) - (5/3)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">10 / (1/12)</gadget>
<output>120</output>

<result>120</result>