+

10

+

10

=

30

................ has money.

30

-

25

=

five

The rest of .......................'s money

five

-

2

=

3 ............................. A, B and C scores.

A

+

B

+

C

=

30

-

three

=

27...............ABC paid all the expenses, including the thermos bottle in 25 yuan, and 2 yuan was put into his pocket by the workers ... This is reasonable. The per capita payment figure is still the same as that of 9 yuan-the thermos bottle used to be in 25 yuan, the workers pocketed 2 yuan, and the total expenditure was in 27 yuan, which had nothing to do with 30 yuan.