C (4,2) = 6 (species).
Therefore, two customers choose gifts in the following way.
6×6=36 (species)
Consider that two customers choose exactly one gift, and there are several possible choices.
First of all, there are four ways to choose the same gift; Then two customers choose two different gifts from the other three, and the choices are as follows.
A (3,2) = 6 (species)
Therefore, among the gifts chosen by two customers, there is just one possible choice.
4×6=24 (species)
So the possibility is
24/36=2/3
Because it is three independent repeated events, the probability of each start is1/a (10,3) =1/720.
The probability of three times is 3x 1/720= 1/240.