Star Wars -- 121 min
First commercial break -- 5 min
The Empire Strikes Back -- 124 minutes
Second commerical break -- 5 min
Return of the Jedi -- 134 minutes
121 + 5 + 124 + 5 + 134 = 389
389 min = 6.48333 hr
How exactly does this end up running for 48 hours, again?