Pat, Kate, and Mark charged a total of 144 hours to a certain project. If Pat charged twice as much time to the project as Kate and 1/3 as much time as Mark, how many more hours did Mark charge to the project than Kate? Choose the correct choice:  A) 18  B) 80  C) 72  D) 90  E) 108

Rationale: "80 all u do is do 2 : 1 : 6 = > 2 x + x + 6 x = 144 = > x = 16 32 : 16 : 96 96 - 16 = 80 answer b"
Answer: B