I am really stuck with this Validity exercise. I do not know how the writer established the answers for row 5, 6 and 7.
Could someone please assist me in providing me the formulas for working out the answers from row 5 to 7.
I have another exercise like it to complete, but I was trying to back-engineer this one.
Just fill in the formula at the bottom of the attachment and send back to me at email@example.com
Thank you very much for your assistance, as I have no books to go by.