Hi Tommy,
In the 5 lb. Probability, Combinatorics, and Overlapping sets section, I have a question regarding problem 26. Could you please explain why we have to multiply the (all three) by 2? I understand that we subtract them for since we would have already counted them in the single subject parts but I did not understand the reason for the multiplication. Also, is there a general formula for computing this?
Thanks and Regards,
Safir
P.S.: Explanation for question 19 in the same section seems to have a mistake. It has 12*11=121 instead of 132. Please correct me if I might have missed something.