A and B start from A and B respectively at the same time and walk towards each other. The speed ratio of A and B is 4:5. After meeting, if A’s speed decreases by 25% and B’s speed increases by 20%, then continue Driving along the original direction, when B arrives at A, A is 30km away from B, then how many kilometers are the distance between A and B?
甲、乙两人分别从A、B两地同时出发，相向而行，甲乙两人的速度比是4：5，相遇后，如果甲的速度降低25%，乙的速度提高20%，然后继续沿原方向行驶，当乙到达A地时，甲距离B地30km，那么A、B两地相距多少km．
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (4/9) - (2/9)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">30 / (1/3)</gadget>
<output>90</output>

<result>90</result>