20 beavers, working together in a constant pace, can build a dam in 3 hours. How many hours C will it take 12 beavers that work at the same pace, to build the same dam?
Pick
A) 2 . B) 4 . C) c = 5 . D) c = 6 . E) 8 .

Rationale: "c . 5 hrs if there were 10 beavers it qould have taken double c = 6 hrs . . so closest to that option is 5 ."
Answer: C