(Profit and loss) The difference between the two distribution schemes = the amount after each word.
2. Double profit time: (big profit-small profit) ÷ The difference between the two distribution schemes = the amount after each word.
3. Double loss: (big loss-small loss) The difference between the two distribution schemes = the amount after each word.
This problem belongs to both interests. The formula is: (14-4)÷(7-5)=5 (room)
5×5+ 14=39 (person) or 5×7+4=39 (person)