We are being asked to express the confidence interval " [tex]0.333 < p < 0.999[/tex] " in the form [tex]P + / - E[/tex]. Well, just take a look at procedure below for the first half of the problem,
[tex]P = ( 0.999 + 0.333 ) / 2,\\E = ( 0.999 - 0.333 ) / 2[/tex]
As you can see, for this first bit we took the average of the numbers, for the second we subtracted one from the other, and now let us approximate each value -
[tex]P = ( About ) 0.666,\\E = ( About ) 0.333[/tex]
And so, [tex]P + / - E[/tex] should be [tex]0.666 + / - 0.333[/tex]. That is our solution!