there are 13 animals in the barn some are ducks and some are pigs there are 42 legs in all how many of each animal are there (ducks have 2 legs and pigs have 4)

There ar 7 of each animal

1=6 (2 legs from the duck, 4 legs from the pig)

2=12 (4 legs from the ducks, 8 legs from the pigs)

3=18 (6 legs from the ducks, 12 legs from the pigs)

4=24 (8 legs from the ducks, 16 legs from the pigs)

5=30 (10 legs from the ducks, 20 legs from the pigs)

6=36 (12 legs from the ducks, 24 legs from the pigs)

7=42 (14 legs from the ducks, 28 legs from the pigs)