1 A familiar per-one model
An empty container gains 8 liters in 4 minutes at a stated constant rate. How many liters are added per minute? Give units. In a time–water graph, which quantity is horizontal?
Your calculation and labels
2 Two nonzero observations
A supplied linear model relates elapsed time t in minutes to total water V in liters for 0 ≤ t ≤ 6. Its points are (2, 14) and (5, 23). Find the change per minute, the total at t = 0 and a rule. Explain why 14 ÷ 2 does not necessarily give the change rate.
Your changes, starting amount and rule
3 Greater rate and greater output
For 0 to 6 minutes, A = 2t + 9 and B = 3t + 2 give total liters. Which has the greater change rate? Which has more water at t = 1? Explain why those questions can have different answers.
Your comparison