Is it safe for two 17-year-old girls to travel to Nanjing? How much does it cost to go there for four days?

4 days is plenty of time, it depends on how you play. Express hotels generally charge 200 to 300 per day, and the cheapest youth hostel seems to be 50 per bed per day. Public transportation costs 150~200 for two people for four days. Most of the attractions are free of charge. You can budget 200 per person. Food and beverage expenses, staple food per person per day are 50. If you go to a more famous restaurant, it will be the same everywhere. . There is no problem with public security in Nanjing, but remember not to go with a Nanjing one-day tour group when you get off the train. No other problems, I wish you a happy journey.