A car travels an average of 45 kilometers per hour from city A to city B, and it takes 4 hours to arrive. If you want to arrive 1 hour earlier, how much more kilometers will you travel per hour than before?
汽车从甲城到乙城，平均每小时行45千米，4小时可以到达，如果要提前1小时到达，每小时比原来多行多少千米？
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">4 / 3</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">45 * (4/3)</gadget>
<output>60</output>

<gadget id="calculator">60 - 45</gadget>
<output>15</output>

<result>15</result>