we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form y=kx
where
k is the constant of proportionality
In this problem we have
x------> number of minutes
y -----> number of paper clips
so
step 1
Find the value of k
K=y/x
looking at the table
we have
For x=6 -----> y=330
substitute
k=330/6
k=55
The linear equation that represent this situation is
y=55x
step 2
Find the missing values
For x=3
substitute in the equation
y=55(3)
y=165 paper clips
For x=5
y=55(5)
y=275 paper clips
For y=440
substitute in the equation
440=55x
solve for x
x=440/55
x=8 minutes