Question

Let $S=\{1,2,3,\dots \dots 10\}$. The number of subsets of $S$ containing only odd numbers is

• A. 15
• B. 31
• C. 63
• D. 7
• E. 5

Answer 1

Answer: (B)

Given set is $\{1,2,3,\dots ,10\}$
The odd numbers in the given set are $1,3,5,7,9$.
$\therefore$ The number of subsets of $5$ containing only number $=2^5-1$
$=32-1=31$