Answer:
Option C: 2 books for $14, 5 books for $35
Explanation:
A proportional relationship between two quantities would always have a constant of proportionality. Thus,
Constant of proportionality, k = y/x
In this case,
x = quantity of books
y = price
Let's see which pair will have a constant of proportionality:
Option A: 4 books for $24,8 books for $40
24/4 = 6;
40/8 = 5.
No constant of proportionality.
Option B: 5 books for $25, 6 books for $36
25/5 = 5
36/6 = 6
No constant of proportionality.
Option C: 2 books for $14, 5 books for $35
14/2 = 7
35/5 = 7
Constant of proportionality, k = 7.
This pair represents a proportional relationship.
Option D: 3 books for $15, 7 books for $28
15/3 = 5
28/7 = 4
No constant of proportionality.