How many mg is 150 mg?

Browsing through a forum (I won't say which), I found this challenging post:

Im probably complicating things can someone sort it out for me.

Upper dose of Wellbutrin is 450mgs a day. If I have 2x150mg sustained release tablets a day does this mean I am having 300mgs or 150mgs?

Is 1x150mg extended release the same as 2x75mg or 2x150mg sustained release?

Is the 150mg extended release like getting 150mg in total over 24 hours(kind of like getting 150/24 each hour) or the effect of being on 150mgs over 24 hours? (hope that makes sense?)

Makes perfect sense! In remedial math class.

[Above swim trunks are also 150 mg. If you wore them for 24 hours, would they be 3600 mg? Or 75?]