human
Yesterday, the newly opened animal shelter received their first 60 animals. They got 20 more cats than dogs. How many cats did they take in?
assistant
Define a variable ** Let c be the number of cats and let d be the number of dogs. We know that c = 20 + d and that the total number of animals is c + d = 60
Write an equation ** Replacing c gives 20+ d + d = 60 animals
Simplify ** Combining like terms and subtracting 20 from both sides, we get 2d = 40
Divide by 2 ** Dividing both sides by 2, we get d = 40/2 = <<40/2=20>>20
How many cats did they take in? ** The shelter therefore received 20 + 20 = <<20+20=40>>40 cats
#### 40