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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

2/3 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

1 1/2 beats per second

Answer 1

To find the average number of heartbeats per second, you can look at the total number of heartbeats over the total time period.

From the provided points, we can find the heartbeats at the end of the time period:

• At \( t = 0 \) seconds, we can assume a starting heart rate of \( 0 \) (although it's not given in the points).
• At \( t = 12 \) seconds, the heartbeats are \( 18 \).

Therefore, the total change in heartbeats is:

\[ 18 - 0 = 18 \text{ beats} \]

The total time from \( 0 \) to \( 12 \) seconds is \( 12 \) seconds.

Now, to find the average rate of heartbeats per second:

\[ \text{Average heartbeats per second} = \frac{\text{Total beats}}{\text{Total time}} = \frac{18 \text{ beats}}{12 \text{ seconds}} = 1.5 \text{ beats per second} = 1 \frac{1}{2} \text{ beats per second} \]

So, the correct answer is:

1 1/2 beats per second