9. The cruise ship "Happy" arrives at the seaport once every 3 days, the cruise ship "Lucky" - once every 4 days, and the cruise ship "Reliable" - once every 5 days. Last Monday, all three cruise ships were in this port. After how many minimum days will they all arrive at this port again, and what day of the week will it be?
9. All three steamships will be in the port after a number of days that is the least common multiple of the numbers 3, 4, and 5, i.e., after $3 \cdot 4 \cdot 5=60$ days. This will be on the fourth day of the week, counting from Tuesday, i.e., on Friday, since $60: 7=8$ (remainder 4).