Question

From a set of integers $1$ to $10$, an integer is selected at random. The probability that the selected integer has no common factor other than $1$ with $10$ is

• A. $\frac{1}{5}$
• B. $\frac{2}{5}$
• C. $\frac{3}{5}$
• D. $\frac{4}{5}$

Answer 1

Answer: (B)

$\frac{2}{5}$

No of integers co-prime with $10$ are $4$ as $1,3,7,9$
The required probability $P=4/10=2/5$