There are currently 5 volunteers, among whom volunteers A1, A2, and A3 are proficient in Russian, and volunteers B1 and B2 are proficient in Korean. Volunteers who are proficient in Russian and Korean

There are currently 5 volunteers, among whom volunteers A1, A2, and A3 are proficient in Russian, and volunteers B1 and B2 are proficient in Korean. Volunteers who are proficient in Russian and Korean are selected from them.

Select one volunteer each who is proficient in Russian and Korean from 5 people, and the basic event space composed of all possible outcomes

Ω={(A1, B1), (A1, B2), (A2, B1), (A2, B2), (A3, B1), (A3, B2)

It consists of 6 basic events, and their occurrence is equally possible ．

Use N to represent "A1 and B2 are not all selected", then its opposite event.N represents "A1 and B2 are both selected",

Since.N={(A1, B2)}***1 basic event,

So P(.N)=16,

According to the probability formula of opposite events, P(N)=1-P (.N)=1-16=56

So the answer is: 56