(Three people spent 9 yuan and one ***27 yuan) equals (the rent was paid to 25 yuan, the waiter hid 2 yuan and one ***27 yuan).

How to add up the money spent and the money hidden by the waiter? Quite confusing.

Explain in detail:

Suppose three complainants are A, B and C respectively.

At the beginning: A: paid 10 yuan; B 10 yuan; C.C. 10 yuan; The waiter has no money; The boss got 30 yuan.

After correction: A: It was handed over to 9 yuan; B Give it to 9 yuan; C to 9 yuan; The waiter took 2 yuan; The boss took 25 yuan.

Let s be the change of their total amount of money (S=0 means that their total amount of money has not changed, that is, S is logical.

So:

Beginning: S = (-10)+(-10)+(-10)+30 = 0 is logical.

After revision: S=(-9)+(-9)+(-9)+2+25=0 is also logical (in fact, the most important thing is the waiter, and the waiter gets the two dollars, so their total money should be increased by two, and the topics around you are here, and the topics are reduced by two).

What do you not know how to ask?