Two people, A and B, are walking towards each other from two places 900 meters apart at the same time. The speed of A is 60 m/s, and the speed of B is 90 m/s. How long has it been since they met? (please use two methods to answer)
A、B二人从相距900米的两地同时相对而行，A的速度是60米/秒，B的速度是90米/秒，请问两人多长时间相遇？(请用两种方法解答)
<gadget id="calculator">60 + 90</gadget>
<output>150</output>

<gadget id="calculator">900 / 150</gadget>
<output>6</output>

<result>6</result>