The value of the constant variation for Nikita's plan is 15.
From the graph given, we can use the pair of points to determine the value of the constant variation :
Using the relationship for constant variation :
- y = kx ; k = constant of proportionality
Now we have :
60 = 4k
k = 60/4
k = 15
Hence, the value of the constant variation for Nikita's plan is 15.