Respuesta :
ratio of 1 to 3 means whenever there are 1 catfish, there are 1 x 3 = 3 trouts.
so if there are 200 catfishes, 200 x 3 = 600
There are 600 trouts there :D
1 catfish : 3 trout
1 catfish x 200 : 3 trout x 200
200 catfish : 600 trout
1 catfish x 200 : 3 trout x 200
200 catfish : 600 trout