Question

Ming wrote the table of points below.

x
y
5
10
10
20
15
30

Which explains whether or not Ming has described a proportional relationship, and why?
Ming has described a proportional relationship because the ordered pairs are linear and the line passes through the origin.
Ming has not described a proportional relationship. Although it is a linear relationship, it does not pass through the origin.
Ming has not described a proportional relationship. Although it passes through the origin, it is not a linear relationship.
Ming has described a proportional relationship because the line does not pass through the origin.

Answer 1

Ming has described a proportional relationship because the ordered pairs are linear and the line passes through the origin.

Reason: y/x = 10/5 = 20/10 = 30/15 = 2, so y = 2x for all points, which is a line through (0,0).