Question 1159016
there are 100 animals in a shelter, some are dogs, some are birds. there are 360 total legs at the shelter. how many of each type of animal are at the shelter?

let number of dogs be x
number of birds be y
there are 100 animals in a shelter,  
x+y=100

there are 360 total legs 
4x+2y=360
divide by 2
2x+y = 180
x+y=100
x+y=100
x=80 (dogs)
20 birds