There are 1, 2, 3, 0 and 5 numbers with which a five-digit number can be formed. What is the probability of forming numbers that are not divisible by five if repetition of digits is not allowed?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Let P A be the probability that the numbers formed are divisible by 5 . Then the probability that the numbers formed are not divisible by 5 is 1 − P A .
If the last digit is 5 , there are 3 × 3 × 2 × 1 × 1 = 1 8 numbers.
If the last digit is 0 , there are 4 × 3 × 2 × 1 × 1 = 2 4 numbers.
The total is 1 8 + 2 4 = 4 2 numbers.
The total numbers that can be formed is 4 × 4 × × 3 × 2 × 1 = 9 6 numbers.
So P A = 9 6 4 2 = 0 . 4 3 7 5 . Finally, 1 − P A = 1 − 0 . 4 3 7 5 = 0 . 5 6 2 5