Question

A two-digit number is formed with the digits $2,5$ and $7$, where repetition of digits is not allowed. Find the probability that the number so formed is a whole number

Answer 1

The possible outcomes when a two-digit number is formed with the digits $2,5$ and $7$ are {$25,27,52,57,72,75$}. Therefore, the number of possible outcomes when a two-digit number is formed with the digits $2,5$ and $7$ is $6$.

Now, the possible outcome of a whole number is {$25,27,52,57,72,75$}, which means the number of favourable outcome is $6$.

Therefore, probability $P$ of a whole number is:

$P=\frac{6}{6}=1$

Hence, the probability of a whole number is $1$.