Question

A two digit number is formed with digits $2,3,5,7,9$ without repetition. What is the probability that the number formed is

(1) an odd number?

(2) an even number?

Answer 1

(i) $P=\frac{n\left(F\right)}{n\left(T\right)}$

$n\left(F\right)=4$ i.e. {$3,5,7$ or $9$ at units place}

$\therefore$ $P=\frac{4}{5}$

(ii) For the number to be even the last digit wil be $2$

$n\left(F\right)=1$

$P=\frac{1}{5}$