Solution:
We have
etc.
So, a natural number of the form may have either
3 or 9 or 7 or 1 at unit's place.
Total number of elementary events= 4
Clearly, only one number has 3 at unit's place.
Favourable number of ways = 1
Hence, required probability=
If where n is a positive integral value, then what is the probability that x will have 3 at unit's place?
We have
etc.
So, a natural number of the form may have either
3 or 9 or 7 or 1 at unit's place.
Total number of elementary events= 4
Clearly, only one number has 3 at unit's place.
Favourable number of ways = 1
Hence, required probability=