雷奥和卢卡斯同在牛奶站工作,他们每天早上都要给一条街道的住户送牛奶。于是他们商量好,雷奥给位于街道左边的住户送牛奶,卢卡斯给位于街道右边的住户送牛奶。已知街道两边的住户数都是相同的。由于雷奥每天都会比卢卡斯早起15分钟,所以他总是帮助卢卡斯给右边街道的前4户人家送奶。当雷奥送完这4户人家的牛奶时,卢卡斯也来了,于是雷奥就开始从左边的第一家 Leo and Lucas worked at the milk station, sending milk to the residents of a street every morning. So they negotiated that Leo gave milk to the residents on the left side of the street and Lucas gave milk to the residents on the right side of the street. It is known that the number of households on both sides of the street is the same. Since Leo every day for 15 minutes earlier than Lucas, so he always help Lucas to the first four people on the right street milk. When Leo sent the milk of the four families, Lucas also came, so Leo started from the first on the left