EXAMPLE 10.7 A machine costs 89 lakh and is deemed to have a scrap value of 10 per cent at the end of its ef- fective life (9 years). Ordinarily, the machine is expected to run for 2,400 hours per annum but it is estimated that 150 hours will be lost for normal repairs and maintenance and further 750 hours will be lost due to staggering. The other details in respect of machine shop are: Wages, bonus and provident fund contribution of each of two operators (each operator is in charge of two machines) (per year) 21,80,000 Rent of the shop (per year) 1,20,000 General lighting of the shop (per month) 10,000 Insurance premium for one machine (per year) 32,000 Cost of repairs and maintenance per machine (per month) 10,000 Shop supervisor's salary (per month) 20,000 Power consumption of machine per hour 20 units @ 6 per unit Other factory overheads attributable to the shop (per annum) 1,60,000 y41 There are four identical machines in the shop. The supervisor is expected to devote one-fifth of time for supervising the machine. Compute a comprehensive machine-hour rate from the above details