conversations.from: human
conversations.value: Chris has twelve marbles, and Ryan has twenty-eight marbles. If they put marbles together in a pile and then each takes away 1/4 of marbles from the pile, calculate the number of marbles remaining in the pile.
conversations.from: assistant
conversations.value: If Chris and Ryan put together their marbles in a pile, the pile will have 12+28 = 40 marbles.
  If they then take 1/4 of the marbles each, every person will receive 1/4*40 = 10 marbles.
  Both of them will have taken a total of 10+10 = 20 marbles.
  The number of marbles remaining in the pile is 40-20 = 20