Scientists send laser signals to the moon from the earth, and receive the signal reflected from the moon after 2.76 seconds. It is known that the speed of light is 300,000 kilometers per second, so what is the distance from the moon to the earth?
科学家从地球上向月球发射激光信号，经过2.76秒收到从月球反射回来的信号．已知光速是每秒30万千米，算一算，月球到地球的距离是多少？
<gadget id="calculator">2.76 / 2</gadget>
<output>1.38</output>

<gadget id="calculator">30 * 1.38</gadget>
<output>41.4</output>

<result>41.4</result>