Answer of the equation of the clock

The riddle is true insofar as the trainee returns two dollars for himself and three dollars for them, but the problem is that when one person gets $ 1, in fact one person pays $ 9, which becomes 9 * 3 = 27 and +2 becomes 29. Dollar!!!!

This is wrong. We should not add 27 to 2 and in fact we should subtract them.

That is, three people paid $ 30, to which the trainee returned three dollars, so they paid $ 27. The intern took $ 2 and they paid $ 25 for the watch.