[quote]
Paper size selected: 8.5 x 11 inch.

Now, if I divide 2400/8.5, 3074/11 = (282,279)

Shouldn't this come out to (300,300) ?
[/qoute]

No, there is .5 inches of margins horizontally, 2400/8 = 300, so .25 on each side, and the vertical printable area is about 10.25. 3074/10.25 = 299.9