Question

On a particularly boring transatlantic flight, one of the authors amused himself by counting the heads of the people in the seats in front of him. He noticed that all 28 of them either had black hair or had a whole row to themselves (or both). Of this total, 27 had black hair and 6 were fortunate enough to have a whole row of seats to themselves. How many of the black-haired people had whole rows to themselves?

Answer 1

The answer is 5.

Explanation:

Total number of people noticed by author = 28

Total number of black haired people = 27

So, total number of non black haired people = 1

Also given that 6 people had whole row of seats to themselves.

Let x be the number of non black haired people who had a whole row to themselves.

Since there is only one person with non black hair and has a whole row to himself because it is mentioned that one person had a row to himself which is non black haired.

Looking at above information we can say that x = 1.

Now we can say that the number of black haired people who had a whole row to themselves = 6-x

or
`6-1=5`

Hence, the answer is 5.