A coach is comparing data about the number of miles Jacob and Otto jogged and the time they spent jogging on week days.

Jacob jogged 3 miles in 30 minutes on Wednesday and 5 miles in 50 minutes on Thursday. Otto jogged 4 miles in 32 minutes on Wednesday and 6 miles in 50 minutes on Thursday.

Whose data shows a proportional relationship between the number of miles jogged and the time spent jogging?
A.
both Jacob's data and Otto's data
B.
only Otto's data
C.
neither Jacob's data nor Otto's data
D.
only Jacob's data

1 answer

To determine whether the data shows a proportional relationship, we need to calculate the ratio of miles jogged to time spent for both Jacob and Otto on each day.

Jacob's data:

  • Wednesday: 3 miles in 30 minutes \[ \text{Ratio} = \frac{3 \text{ miles}}{30 \text{ minutes}} = \frac{3}{30} = \frac{1}{10} \text{ miles per minute} \]
  • Thursday: 5 miles in 50 minutes \[ \text{Ratio} = \frac{5 \text{ miles}}{50 \text{ minutes}} = \frac{5}{50} = \frac{1}{10} \text{ miles per minute} \]

Both days for Jacob give a consistent ratio of \( \frac{1}{10} \), indicating a proportional relationship.

Otto's data:

  • Wednesday: 4 miles in 32 minutes \[ \text{Ratio} = \frac{4 \text{ miles}}{32 \text{ minutes}} = \frac{4}{32} = \frac{1}{8} \text{ miles per minute} \]
  • Thursday: 6 miles in 50 minutes \[ \text{Ratio} = \frac{6 \text{ miles}}{50 \text{ minutes}} = \frac{6}{50} = \frac{3}{25} = 0.12 \text{ miles per minute} \]

These two ratios for Otto are \( \frac{1}{8} \) (0.125) and \( \frac{3}{25} \) (0.12), which are not equal, indicating that his data does not show a proportional relationship.

Since Jacob's data shows a consistent ratio while Otto's data does not, the answer is:

D. only Jacob's data