high-speed train from city A to city B travels an average of 240 kilometers per hour and can arrive in 4 hours. After the speed is increased, the average speed is 320 kilometers per hour, how many hours can it be reached?
甲城开往乙城的高速列车，平均每小时行240千米，4小时可以到达．提速后，平均每小时行320千米，几小时可以到达？
<gadget id="calculator">4 / 320</gadget>
<output>1/80 = around 0.0125</output>

<gadget id="calculator">240 * (1/80)</gadget>
<output>3</output>

<result>3</result>