To find the ratio at which the constant of proportionality appears, we can analyze the relationship between the scoops of raspberry and the cups of lemonade.
According to the problem, you need to add 2 scoops of raspberry to every 5 cups of lemonade. This can be expressed as the ratio of raspberry scoops to lemonade cups, which is:
\[ \frac{\text{scoops of raspberry}}{\text{cups of lemonade}} = \frac{2}{5} \]
Now we should look for this ratio in the provided options. The equivalent ratio can also be written as:
- (2, 5)
This matches the given relationship.
The other options you provided are:
- (1, 2.5)
- (2.5, 1)
- (5, 2)
None of these options correctly represent the ratio of the needed amount of raspberry scoops to lemonade cups.
Therefore, the correct answer is (2, 5).