Which method is economically efficient if the wage rate is (i) $5 an hour, (ii) $50 an hour, and

(iii) $500 an hour?

Four methods of completing a tax return and the time taken are: Using a laptop, 1 hour; a calculator, 12 hours; a calculator and paper and pen, 12 hours;
and a pen and paper, 16 hours. The laptop and its software cost $1,000, the calculator costs $10, and the pen and paper cost $1.