Question

A question paper has 5 questions. Each question has an alternative. The number of ways in which a student can attempt at least one question is?

• A. $2^5-1$
• B. $3^5-1$
• C. $3^4-1$
• D. None of these

Answer 1

The correct option is A $2^5-1$

Each question have $2$ choices (answer the question or answer its alternative or leave the question).

$\therefore$, total number of ways$=2\times 2\times 2\times 2\times 2=2^5$ ways

But in these $2^5$ ways, there is one way in which no question is attended.

$\therefore$Required number of ways$=2^5-1$