A man has 7 friends. In how many ways he can invite one or more of the

1.	A man has 7 friends. In how many ways he can invite one or more of them for a tea party(A) 128(C) 127(B) 256(D) 130
Answer» Each of the 7 friends could be present or not present (2 cases) at the party giving total of2^7scenarios. Since at least one must be present we exclude the case that none of them is present. So the answer would be: 2^7−1=127.

A man has 7 friends. In how many ways he can invite one or more of them for a tea party(A) 128(C) 127(B) 256(D) 130

Answer»

Each of the 7 friends could be present or not present (2 cases) at the party giving total of2^7scenarios.

Since at least one must be present we exclude the case that none of them is present. So the answer would be:

2^7−1=127.