Conditional probability 2 scenarios

[Collins]

There are 4 books being sold in the bookshop : A, B, C, D.
We know that 20% of the male customers buy book A at least once a week, 55% buy book B at least once a week, 25% buy book C at least once a week and 15% buy book D at least once in a month.
We also know that 32% of the female customers by book A at least once a week, 80% buy book B at least once a week, 40% buy book C at least once a week and 65% buy book D at least once a week.
The ratio of male customers to female is 3 to 1.
The goal is to calculate a probability of meeting male and a female in the shop, given that each customer decided to purchase books A, B, C and the average frequency of shopping is once a week.

I believe the solution is to calculate joint probability of male and female probabilities of buying ABC set. Maybe I'm wrong so I could use some help. Also I'm not sure if shopping frequency matters.

 

[Dr.Peterson]

How long does one stay in the shop when buying a book? I don't think the problem can be solved as stated, unless you make some assumption that they stay there all day, or that everyone buys books at the same hour of the day.

Also, why in the world would anyone buy the same book every week?

I suspect there is a language issue here. Or else the whole thing is a joke.

 

[Collins]

How long does one stay in the shop when buying a book? I don't think the problem can be solved as stated, unless you make some assumption that they stay there all day, or that everyone buys books at the same hour of the day.

Also, why in the world would anyone buy the same book every week?

I suspect there is a language issue here. Or else the whole thing is a joke.

Yeah that's exactly what I meant by "I'm not sure if shopping frequency matters". I guess you should make an assumption that they go in and go out at the same time with the same periodicity (at least once a week). As for books it's just a variable. It could be clothes, food etc.

Sorry if it's too abstractional. But that's just the way it is. I just wanna get an idea of how could you possibly proceed with the given conditions.

 

[Dr.Peterson]

So, you made up the problem, and are free to modify it?

What is your goal here? In order to turn it into a doable problem, we'll have to know what parts are important to you. As it is, there are too many things that just don't make sense.