the equation of the direct variation is
y = k x, where
k is the constant of variation
Let x represents the number of volunteers
y represents the number of houses
let us choose a point from the graph to find k
The point (5, 0.5) lies on the graph
x = 5 and y = 0.5
Substitute them in the equation above
0.5 = k(5)
0.5 = 5k
Divide both sides by 5 to find k
0.5/5 = 5k/5
0.1 = k
the equation of variation is y = 0.1 x
To find the number of houses with 60 volunteers
Substitute x by 60
y = 0.1(60)
y = 6
The number of houses can be built with 60 volunteers is 6