conversations.from: human
conversations.value: I'm completely lost with this math problem: Every year 20 ducks from a flock are killed but another 30 are born.  The original flock size is 100 ducks.  After 5 years they join with another flock of 150 ducks.  How many ducks are in the combined flock?
  Can you give me a hand?
conversations.from: assistant
conversations.value: The original flock gains 30-20=10 ducks per year
  So after 5 years they have gained 10*5=50 ducks
  So the original flock has 100+50=150 ducks
  So the combined flock has 150+150=300 ducks