8.2. Double Line Graphs http://www.ck12.org
a. Who won the race? How do you know?
b. Between what times did Thomas (blue) appear to slow down? How do you know?
c. Between what times was Abby (red) ahead of Thomas? How do you know?
d. At what time did Thomas pass Abby? How do you know?
Answer:
a. Thomas (blue) won the race, because he finished the 500 yards in the least amount of time.
b. Between 20 and 40 seconds, Thomas (blue) seems to slow down, because the slope of the graph is less steep.
c. Between 0 and 57 seconds, Abby (pink) is ahead of Thomas (blue). You can see this, because the pink line is
above the blue line.
d. At 57 seconds, Thomas (blue) passes Abby (pink). From this point onward, the blue line is above the pink line,
meaning Thomas is running faster 100 yard intervals.
Example B
Brenda and Ervin are each planting corn in a section of garden in their back yard. Brenda says that they need to put
fertilizer on the plants 3 to 5 times per week. Ervin contradicts Brenda, saying that they need to fertilize only 1 to 2
times per week. Each gardener plants his or her garden of corn and measures the heights of their plants. The graph
for the growth of their corn is found below: