Row: |______Y_______|_____X____|
Y = Size 10. 4 people are wearing hats.
X = Unknow size. Everyone is wearing hats.
Rephrasing the question: X + Y = ?
(1) 5 of the 6 people from the right are wearing hats.Since we know that every person after the 10-th position is wearing a hat, we can infer that there's a overlap between the "6 people from the right" and the "10 people from the left". Is this information sufficient? No, it's not. The size can be from 11 (since we havce 4 people with hat in 10 first positions, we need at least one more person with hat) to 15 (since everyone after the 10-th position must wear a hat, 5 from this 6 people can be after 10-th position).
Eliminate answer choices A and D.
(2) 3 of the 8 people from the left are wearing hats.Ok. So we now know that, in positions 9 and 10 we have exactly 1 person wearing a hat and 1 person no wearing a hat. Is it sufficient? No, it's not. We can have know infinite options, since we do not have any bound to the right after 10-th position.
Eliminate answer choice C.
Statements (1) and (2)Plugging both information we can have:
Row: |___8____|_2_|___X___|
In the 8 first positions, 3 hats. Between positions 9 and 10 we have one more hat.
If we have H in position 10, with statement (1) we can have 1 option:
<8 initial positions>NH HHHH. Size = 8 + 6 = 14. Where H represent a person wearing hat and N represent a person not wearing a hat.
If we have H in position 9, with statement (1) we can have 2 options:
<8 initial positions>HN HHHH. Size = 8 + 6 = 14.
<8 initial positions>HN HHHHH. Size = 8 + 7 = 15.
Therefore, we are not able to determine the row length only with the information provided. Eliminate answer choice C.
Answer = E.