It is urgent to help solve a mathematical probability problem

1. No matter who draws first, the probability of three people is the same, so asking B is the same as asking others.

2.b begins to draw lots, and she has 15 schemes in front of her (C6/2 means to choose two at will in six days, and there is no difference in order).

3. 15 scheme, there are five schemes with Saturday (6 & 1，6 & amp； 2，6 & amp； 3，6 & amp； 4，6 & amp； 5)

4. So the probability is 5/ 15= 1/3.