Lebron James has an offensive efficiency of 50%
Dwayne Wade has an offensive efficiency of 55%
Chris Bosh has an offensive efficiency of 40%
Given that Lebron James controls 1/2 of all possessions, Dwayne Wade controls 1/4 of all possessions, and Chris Bosh controls 1/8 of all possessions, what is their combined offensive efficiency?
(You can assume that no possession is controlled by 2 or more of these 3)