Question

A two digital number is formed with digitals 2,3,5,7,9, without repetition. what is the probability that the number formed is 1)an odd number. 2)a multiply of 5.​

Answer 1

Answer:

Digits are {22,23,25,27,29,32,33,35,37,39,52,53,55,57,59,72,73,75,77,79,92,93,95,97,99}

∴Total digits are 25

Odd numbers are 20

∴ probability that an odd number is formed is

25

20

=

5

4

a multiple of 5

Numbers which are multiple of 5 are

{25,35,55,75,95}

∴ probability of multiple of 5 is

25

5

=

5

1