20 beavers , working together in a constant pace , can build a dam in 18 hours . how many hours will it take 12 beavers that work at the same pace , to build the same dam ?
total work = 20 * 18 = 360 beaver hours 12 beaver * x = 360 beaver hours x = 360 / 12 = 30 answer : c
divide(multiply(18, 20), 12)