conversations.from: human
conversations.value: 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?
  Solve this problem.
conversations.from: assistant
conversations.value: 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
  Replacing c gives 20+ d + d = 60 animals
  Combining like terms and subtracting 20 from both sides, we get 2d = 40
  Dividing both sides by 2, we get d = 40/2 = 20
  The shelter therefore received 20 + 20 = 40 cats