We know that Chelsea and Bradyn both draw a graph and we want to know something about the $y -$ intercepts of their graphs. Let's look at each case separately!

Bradyn's graph

Bradyn graphs a line that passes through the origin, which is the point $(0, 0) .$ The $y -$ intercept is the $y -$ coordinate of the point on a graph where the line crosses the $y -$ axis. For the line that passes through the origin, the $y -$ coordinate is $0,$ and therefore the $y -$ intercept is $0 .$

Chelsea's graph

Chelsea graphs a proportional relationship. When two variables are proportional, the graph of this relationship is a straight line. Let's look at the graphs of a few proportional relationships.

These graphs are all straight lines that pass through the point $(0, 0),$ which is the origin of a coordinate plane. This point lies on the $y -$ axis, so the $y -$ coordinate of the point is the $y -$ intercept of the graphs. Therefore, if Chelsea draws a proportional relationship, we know that its $y -$ intercept is $0 .$

Conclusion

The graphs of both students have the $y -$ intercepts equal to $0 .$ In fact, they both draw graphs of the same type, because the graph passing through the origin is a graph of a proportional relationship.

Exercise