and B live in the same yard. On this day, they leave the hospital at the same time and go to the upper half of the unit 900 meters apart. A walks 90 meters per minute, and B walks 60 meters per minute. How far is B from the unit when A and B meet on the road?
甲、乙两人住同一个院子，这天两人同时出院门到相距900米的单位上半，甲每分钟行90米，乙每分钟行60米，甲到单位后发现忘带钥匙又原路回家去取，当甲、乙两人在路上相遇时乙离单位有多远？
<gadget id="calculator">90 + 60</gadget>
<output>150</output>

<gadget id="calculator">2 / 150</gadget>
<output>1/75 = around 0.013333</output>

<gadget id="calculator">900 * (1/75) * 60</gadget>
<output>720</output>

<gadget id="calculator">900 - 720</gadget>
<output>180</output>

<result>180</result>