The following six months of data were collected on electricity cost and the number of machine hours in a factory.

Electricity cost Machine hours Month June R25,160 4,500 July R26,170 4,810 August R27,250 5,120 September R26,680 5,010 October R27,950 5,430 November R 27,500 5,190

Required: 1. Using the high-low method compute the variable rate for the electricity cost. (4 marks) 2. Using the high-low method compute the fixed cost of electricity. (3 marks) 3. Estimate the total electricity cost to be incurred in December if 5,300 machine hours are incurred.