The distance between A and B is 450 kilometers. Two trains depart from the two places at the same time and meet each other in 4.5 hours. The speed ratio of the fast train and the slow train is 3:2. Find the speed of the slow train.
甲、乙两地相距450千米，两列火车同时从两地相对开出，4.5小时相遇，快、慢两车的速度比是3：2，求慢车的速度．
<gadget id="calculator">450 / 4.5</gadget>
<output>100</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

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

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>