Two cars, A and B, start from places a and b at the same time. When they meet, A passes (1/3). When car B arrives at point a, A is still 15 kilometers away from point b. How many kilometers away?
甲、乙两辆汽车分别从a、b两地同时出发，相遇时甲行了(1/3)，当乙车到达a地时，甲离b地还有15千米，相距多少千米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(1/3) / (2/3)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">15 / (1/2)</gadget>
<output>30</output>

<result>30</result>