Hi, I solve this question using P(G or H but not both) = P(G) + P(H) - 2P(G).P(H) and got the same answer. I just understood the solution provided but somehow it doesn’t feel very intuitive. What is it I am missing or not practicing to see this better?

Want to avoid creating multiple threads but for this question from the same exercise section of data analysis, why do we only have 20 total possible of products? Shouldn’t we use combination formula = (N!) / (N-R)! to solve this because we can also have (1x2), (1x3), and so forth?

Same thing - you memorised the formula, they derived it.

Shouldn’t we use combination formula = (N!) / (N-R)!

No, why?

we can also have (1x2), (1x3), and so forth?

You can do that - answer won’t change.

(P.S: in the future, create separate threads for each problem. This helps future students viewing the same problem)

Thank you, and also will be mindful of creating on thread per issue.

Why not using the combination formula → because I thought it could git into N=9 and R=2 (given it is a product of two values).

Because you can’t pick two values from set 1. If you’re combining the two sets into one, then you’re right.

ahhh okay, because x only refer to Set S while Y is Set T instead of xy from a set S or T. Is that what you mean by we are not combining two sets into one?

Correct. T does not include every element from X and Y.

Thank you, sir!