Question

The relationship between the cost of books and number of books is shown below as a graph.


The constant of proportionality for the given graph is

• A. 3
• B. 6
• C. 9

Answer 1

The correct option is A 3

From the graph, let us draw three points A, B and C on the graph.


From the graph, we can see that the coordinates of the point A is (1,3) and coordinates of the point B is (2,6)

So, for the first point A:
Value of x = 1
Value of y = 3

And for the second point B:
Value of x = 2
Value of y = 6

∴ Constant of proportionality of the graph will be = $\frac{y}{x}$
= $\frac{3}{1}$ = $\frac{6}{2}$= 3

So, constant of proportionality will be 3.