A typical concept problem of stealing-"Where did the remaining dollar go?"

Three people stayed in 30 yuan, and the boss returned to 5 yuan, which means that the three of them spent a total of 25 yuan; Then the younger brother paid back one yuan each, which means that they spent a total of 28 yuan, plus the 2 yuan that the boss's younger brother took, which happened to be 30 yuan.

Total amount of money (30)= amount of money spent by people staying in hotels (27)+ amount of money left on them (3).

2. Total amount of money (30)≠ Money spent by people staying in hotels (27)+ Money stolen by my brother (2)

3. Money spent by hotel guests (27)= money earned by boss (25)+ money stolen by younger brother (2)