1.y varies directly with x
2.substitute the value of x and y in the equation below
y=kx
where k is the constant term
60=20k
k=60\20
k=30
:y=30x.....is the law
To find y when x is 12
You reinstate the law which is y=30x
Then substitutes the value of x to determine y
y=30*12
y=36.
