Teacher Zhang rides a bicycle at a speed of 15 kilometers per hour, and it takes 30 minutes to go from home to school. It only takes 18 minutes to switch to riding an electric car now. How many kilometers does Mr. Zhang travel per hour on an electric bike?
张老师骑自行车以每小时15千米的速度，从家到学校，需30分钟．现在改骑电动车，只需18分钟．张老师骑电动车每小时行驶多少千米？
<gadget id="calculator">30 / 18</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">15 * (5/3)</gadget>
<output>25</output>

<result>25</result>