To analyze the data provided for Kimberly and Katrina, we need to calculate the jumping jacks per second for each individual, identify their initial jumping jacks before timers started, and assess whether their relationships are proportional.
a. Jumping Jacks per Second
To find the jumping jacks per second for each person, divide the number of jumping jacks by the time taken in seconds.
Kimberly:
- At 3 seconds: \( \frac{17}{3} \approx 5.67 \)
- At 8 seconds: \( \frac{37}{8} = 4.625 \)
- At 12 seconds: \( \frac{53}{12} \approx 4.42 \)
- At 16 seconds: \( \frac{69}{16} \approx 4.31 \)
Average for Kimberly: \[ \text{Average} = \frac{5.67 + 4.625 + 4.42 + 4.31}{4} \approx 4.77 \text{ jumping jacks/second} \]
Katrina:
- At 2 seconds: \( \frac{10}{2} = 5 \)
- At 5 seconds: \( \frac{25}{5} = 5 \)
- At 12 seconds: \( \frac{60}{12} = 5 \)
- At 20 seconds: \( \frac{100}{20} = 5 \)
Average for Katrina: \[ \text{Average} = \frac{5 + 5 + 5 + 5}{4} = 5 \text{ jumping jacks/second} \]
Conclusion for Part a: Katrina is doing more jumping jacks per second (5 jacks/second) compared to Kimberly (average of 4.77 jacks/second).
b. Initial Jumping Jacks
To determine how many jumping jacks each person had completed before the timer started, we look at their performance at 0 seconds. Since there’s no explicit information provided, we can deduce from the given values:
- Kimberly: Assuming she started at 0 seconds: 0 jumping jacks before timer
- Katrina: Assuming she also started timer at 0 seconds: 0 jumping jacks before timer
Conclusion for Part b: Both persons had completed 0 jumping jacks before the timer started.
c. Proportional Relationship
A relationship is considered proportional if the ratio of the quantities remains constant.
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Kimberly's Data:
- \( \frac{17}{3}, \frac{37}{8}, \frac{53}{12}, \frac{69}{16} \) - The ratios are different.
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Katrina's Data:
- \( \frac{10}{2} = 5, \frac{25}{5} = 5, \frac{60}{12} = 5, \frac{100}{20} = 5 \) - The ratios are consistent and equal (5).
Conclusion for Part c: Katrina shows a proportional relationship since her jumping jacks per second remains constant at 5, unlike Kimberly's varying ratios.
To summarize:
- a. Katrina is doing more jumping jacks per second.
- b. Both had completed 0 jumping jacks initially.
- c. Katrina shows a proportional relationship.