Question

Identify the different phases of the law of variable proportions from the following schedule. Give reasons for your answer.

$\begin{array}{cccccc}\text{Units of variable input}& 1& 2& 3& 4& 5\\ \text{TPP (units)}& 4& 9& 13& 15& 12\end{array}$

Answer 1

$\begin{array}{cccccc}\text{Units of variable input}& 1& 2& 3& 4& 5\\ \text{MPP (units)}& 4& 5& 4& 2& -3\end{array}$

The three phases of the law of variable proportions are identified from the behaviour of MPP.

(i) The first phase is upto two units because MP is increasing

(ii) The second phase is from three units to four units because MP is falling but positive

(iii) The third phase is from fifth unit because MP is negative.