conversations.from: human
conversations.value: A bar of steel weighs twice the mass of a bar of tin. If a steel bar also weighs 20 kgs more than a copper bar and a copper bar weighs 90 kgs, calculate the total weight of a container with 20 bars of each type of metal.
  What is the solution?
conversations.from: assistant
conversations.value: The total weight of 20 bars of copper is 20*90 = 1800kgs
  If a copper bar weighs 90 kgs, and a steel bar weighs 20 kgs more than a copper bar, the weight of a steel bar is 90+20 = 110 kgs.
  If a bar of steel weighs 110 kgs, 20 bars will weigh 20*110 = 2200kgs
  The total weight of 20 bars of copper and steel is 2200+1800 = 4000 kgs
  A bar of steel weighs twice the mass of a bar of tin, meaning a bar of tin weighs 110/2 = 55 kgs
  The total weight of 20 bars of tins is 55*20= 1100 kgs
  The total weight of 20 bars of each metal is 4000+1100 = 5100 kgs