Question

Ramesh has four friends. In how many ways can he invite one or more of them for dinner?

• A. 15
• B. 11
• C. 16
• D. 20

Hint:

Number of ways to select at least one from $n$ items = $2^n - 1$

Answer 1

The Correct Option is A

Concept: Each friend can either be invited or not invited. This leads to combinations based on subsets.

Step 1: Total possible subsets.
For 4 friends: \[ \text{Total subsets} = 2^4 = 16 \]

Step 2: Exclude empty set.
Since at least one friend must be invited: \[ 16 - 1 = 15 \]

Step 3: Final conclusion.
Thus, number of ways: \[ 15 \]