conversations.from: human
conversations.value: Find the answer to the math problem: It takes Matthew 3 minutes to dig a small hole for shrubs and 10 minutes to dig a large hole for trees.  How many hours will it take him to dig 30 small holes and 15 large holes?
conversations.from: assistant
conversations.value: It takes 3 minutes to dig a small hole and he needs to dig 30 small holes so it will take 3*30 = 90 minutes
  It takes 10 minutes to dig a large hole and he needs to dig 15 large holes so it will take him 15*10 = 150 minutes
  It will take 90 minutes to dig the small holes and 150 minutes to dig the large holes for a total of 90+150 = 240 minutes
  There are 60 minutes in 1 hour and he needs to dig for 240 minutes so that's 240/60 = 4 hours