Using the 2018 sales figures as a trend, with a spreadsheet, develop a sales forecast for January to December with the increase in workflow enabled by each machine purchasing option. Regina has calculated that she obtains a net margin of 5, 9.5 and 15 per cent respectively for the routine maintenance work, small repair work and large repair work. Using these assumptions and assuming she buys the machine in December 2018 ready for January 2019, determine:

a Which machine purchase offers the best (shortest) payback in 2019 and how many months will it take for each option?

b Which option will generate the greatest revenue increase in terms of dollars under the assumptions Regina has applied?

c Which option provides the best forecast net percentage margin return on total revenue (net margin in dollars/total sales in dollars)?