There are three cars A, B, and C, each starting from a certain place at a certain speed and going in the same direction. B starts 10 minutes later than C, and catches up with C 40 minutes after departure. A starts 20 minutes later than B. After departure, One hour and one minute to catch up with C, may I ask: How many minutes does it take for A to catch up with B?
有甲、乙、丙三辆汽车，各以一定的速度从某地出发同向而行，乙比丙晚出发10分钟，出发后40分钟追上丙，甲比乙晚出发20分钟，出发后1小时分钟追上丙，请问：甲出发多少分钟后才能追上乙？
<gadget id="calculator">10 + 20 + 60</gadget>
<output>90</output>

<gadget id="calculator">90 / 60</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">10 + 40</gadget>
<output>50</output>

<gadget id="calculator">50 / 40</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(3/2) / (5/4)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) - 1</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / (1/5)</gadget>
<output>100</output>

<result>100</result>