gremather wrote:
I am bit confused with the last bit of your answer. If 50% of the guests who wore jackets didn't wear ties, then shouldn't the "No Tie and Jacket" cell be 50? And so the total # of jackets will be 90. So 90%? But 90% is not in the answers so I could be wrong.
If 50% of the guests who wore jackets didn't wear ties means
They are only wearing JacketsLet the total number of people wearing jackets be \(J\)
people wearing
only jackets = \(0.5J\)
people wearing
both jackets and ties = 0.40(total)
So,
people wearing jackets = people wearing
only jackets + people wearing
both jackets and ties
\(J = 0.5J + 0.40(total)\)
\(0.5J = 0.40(total)\)
\(J = 0.80(total)\)
Hence, option E