Game Theory Help

Im stuck on q6 part 6 and part 7on the June 2013 D2. Link To Paper : http://www.ocr.org.uk/Images/175287-question-paper-unit-4737-01-decision-mathematics-2.pdf

Mark scheme : http://www.ocr.org.uk/Images/176262-mark-scheme-unit-4737-decision-mathematics-2-june.pdf

Can someone explain to me why the answer, p=3/5. In order to get the maximum p value, can you not use the intersection between y=3 and 3p+1. This would give P the value of 2/3 which is bigger tan 3/5.

For the very last question, I just dont understand and would really appreciate someone explaining it to me
Thanks

The maximum value of p is the found from the point which is Highest from the bottom. Imagine drawing a perimeter from the bottom and continuing onto to next line as soon as you reach a point of intersection. This is the area that you need to consider and then find the highest of those points.

Yes I understand that, so the highest point is the intersection at E=3 and the line 1+3p. The mark scheme does not say this but instead the line 1+3p and 4-2p. I dont understand this?