Question

Take a moment to recap. Which relationship is a function? Remember, a function is a special type of rule where each input has only one possible output.
number of weeks old
Input Output Arrow
multiply by 7
Input Output Arrow
number of days old




Number of weeks Number of days
3 21
7 49
10 70


The number of days is

of the number of weeks.


Number of weeks Weight in pounds
8 2
8 17
8 7


The weight in pounds is

of the number of weeks.
is a function
not a fuction

Answer 1

Let's evaluate each relationship to determine if it is a function.

1. **Number of weeks to number of days:**
- Given the relationship where the input is the number of weeks old and the output is the number of days old, the rule is to multiply the number of weeks by 7 (since 1 week = 7 days). The data provided shows:
- 3 weeks → 21 days
- 7 weeks → 49 days
- 10 weeks → 70 days
- Each input (number of weeks) corresponds to exactly one output (number of days). Therefore, this relationship **is a function**.

2. **Number of weeks to weight in pounds:**
- In this case, the data provided shows:
- 8 weeks → 2 pounds
- 8 weeks → 17 pounds
- 8 weeks → 7 pounds
- Here, the input (number of weeks) of 8 corresponds to multiple outputs (2 pounds, 17 pounds, and 7 pounds). Since one input can have multiple outputs, this relationship **is not a function**.

To summarize:
- The relationship of number of days as a function of the number of weeks **is a function**.
- The relationship of weight in pounds as a function of the number of weeks **is not a function**.