Answer: The required value of x is 36.
Step-by-step explanation: Given that the variables x and y varies directly. Also, x = 12 when y = 3.
We are to find the value of x when y = 9.
Given that x and y varies directly. So, we have
where 'k' is the constant of proportionality.
Given that x = 12 when y = 3, so from equation (i), we have
Substituting the value of k in equation (i), we have
When y = 9, we get from equation (ii) that
Thus, the required value of x is 36.