1. In how many ways can I invite one or more of friends to a dinner? 2.8 friends shake hands mutually.Find the total number of handshakes.For each shake hand we need two persons.

Asked by  | 13th Mar, 2013, 09:26: PM

Expert Answer:

1) Your first question is incomplete. However, these types of questions can be solved in the following manner.
Suppose a person has 6 friends. And we need to find out the number of ways in which he can invite one or more of them at a dinner.
Following will be the answer.

He may invite one or more friends by selecting either one, two three, four, five or six out of the 6 friends. So total number of ways = 6C1 + 6C2 + 6C3 + 6C4 + 6C5 + 6C6
Since there are 8 friends, and each handshake requires 2 friends, this is the same as choosing 2 people out of 8 people.
Thus, the answer will be 8C2 handshakes

Answered by  | 14th Mar, 2013, 03:57: PM

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