Cars A and B start from places A and B respectively and drive toward each other. When starting out, the speed ratio of A and B is 5:4. After meeting, A’s speed decreases by 20%, and B’s speed increases by 20%. In this way, when A reaches point B, B is still 10 kilometers away from point A. So how far is the distance between A and B?
甲、乙两车分别从A、B两地出发，相向而行．出发时，甲、乙的速度比是5：4，相遇后，甲的速度减少20%，乙的速度增加20%这样，当甲到达B地时，乙离A地还有10千米．那么A、B两地相距多少千米．
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5 * (4/5)</gadget>
<output>4</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">4 * (6/5)</gadget>
<output>24/5 = around 4.8</output>

<gadget id="calculator">4 / (24/5)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 / (5/6)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(4/9) * (6/5)</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">1 - (4/9) - (8/15)</gadget>
<output>1/45 = around 0.022222</output>

<gadget id="calculator">10 / (1/45)</gadget>
<output>450</output>

<result>450</result>