An octopus has 8 tentacles and 1 head. A jellyfish has 20 tentacles and no head. A cow has 4 legs and 1 head. Farmer Brown, who only raises octopi, jellyfish and cows on her farm, has animals with a total of 17 heads, 196 tentacles and 20 legs. How many animals does she have?
since there are 17 heads there are 17 animals so far in our count
20 legs means 5 cows
then there are 17-5 = 12 octipi
196 tentacles 12 octipi * 8 = 96 tentacles are octipi the remaining tentacles are jellyfishes 196 - 96 = 100
100 / 20 = 5 jellyfish
total 22 animals
since there are 17 heads there are 17 animals so far in our count
20 legs means 5 cows
then there are 17-5 = 12 octipi
196 tentacles 12 octipi * 8 = 96 tentacles are octipi the remaining tentacles are jellyfishes 196 - 96 = 100
100 / 20 = 5 jellyfish
total 22 animals