Question

at a gathering of 30 people, there are 20 people who all know each other and 10 people who know no one. people who know each other hug, and people who do not know each other shake hands. how many handshakes occur within the group?

Answer 1

Since there are 10 persons in the group who do not know one another, the real number of handshakes will be 45.

What is combination?

In probability theory and other branches of mathematics, the term "combination" refers to a succession of results where the order is irrelevant. A combination is a selection of all or a portion of a group of items, regardless of the sequence in which the items are chosen. Combinations and permutations may appear to be synonyms. However, they are defined differently in probability theory. Combinations: The sequence of results is irrelevant. Permutations: The sequence of events matters.

Here,

Total number of handshakes = 10C2 = (10 × 9)/2 = 45 handshakes.

When 10 people are shaking hands, each one will shake hands with 9 others.

The total number of handshakes in actual = 90/2 = 45 handshakes.

The total number of handshakes in actual will be 45 handshakes as there are 10 people in the group who do not know each other.

To know more about combination,

brainly.com/question/20211959

#SPJ4