If it’s the weekend, the chances of allison going to the store is 4/5. if its a weekday, the chances are 2/5. given that allison will not go to the store, what is the probability that it’s the weekend?

Given that it's a weekend, chances of Allison going to the store is 4/5
If its a weekday, the chances are 2/5.
Given that Allison will not go to the store the probability that it’s the weekend? will be:
1-(it's a weekend and Allison will go to the store)
=1-4/5
=1/5

1/5

This makes absolutely no sense at all young man/women