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

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