Graphs of Proportional Relationships Quick Check
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Question
Use the image to answer the question.
A graph shows an x-axis representing time in seconds ranging from 0 to 12 in increments of 2. The y-axis represents heartbeats ranging from 0 to 18 in increments of 3. The graph shows a line representing resting heart rate. The line passes through the following plotted points: left parenthesis 4 comma 6 right parenthesis; left parenthesis 6 comma 9 right parenthesis; left parenthesis 10 comma 15 right parenthesis; and left parenthesis 12 comma 18 right parenthesis.
What is the average number of heartbeats per second?
(1 point)
Responses
23 beat per second
Start Fraction 2 over 3 End Fraction beat per second
3 beats per second
3 beats per second
2 beats per second
2 beats per second
112 beats per second
To find the average number of heartbeats per second, we need to divide the total number of heartbeats by the total time.
Looking at the graph, we can see that the heart rate increases linearly, meaning it is proportional.
The starting point is (4, 6) and the ending point is (12, 18).
The total number of heartbeats is 18 - 6 = 12.
The total time is 12 - 4 = 8.
Therefore, the average number of heartbeats per second is 12/8 = 3 beats per second.