If labor costs $10 per unit and machines rent for $20 apiece, a movement along a given isocost line might imply a substitution of Solution Answer As per the concept of ISo cost line a producer firm will able to substitute for 1 unit of Machinery for 2 units of labor as the ratio of substitution is 2:1 , and the price paid for 2 labor is equal for a rent for 1 machine . .