Assume that 2 digits are selected
at random from the set {1,3,5,7,9} and are arranged in random order. What is the probability that the resulting 2-digit number is less than 90?

Question

Assume that 2 digits are selected
at random from the set {1,3,5,7,9} and are arranged in random order. What is the probability that the resulting 2-digit number is less than 90?

anonymous · Answer

from 2 digits are selected, each number can repeat or no?

anonymous · Answer

i'm going to assume they can repeat.

anonymous · Answer

OK..

anonymous · Answer

for solution : 
Probability of an event happening = Number of ways it can happen/Total number of outcomes
= 4(5)/5(5) = 20/25 = 4/5