a) As an operations manager for my region, GRIDCO, Ghana, Mr. Voltage is responsible for ensuring that transmission lines are operational at all times. This also means that branches and twigs from neighboring trees are not permitted to interfere with or touch the lines. As a result, he engages many tree contractors. He agrees with a contractor on the amount of trees he must prune and a flat sum payment. I prefer not to pay him per tree pruned. I'm used to it - lump sum - and contractors are fine with it. Trees grow best during the rainy season, and he hires contractors for a year, from this rainy season to the next. He has the authority to instruct them which trees to prune and when. He counts the trees as the contractor prunes them and divides the overall number of trees pruned by the total number of tees to prune. He gets a cumulative percentage of completion. When he multiplies that percentage by the lump sum, he gets the total amount he pay/owe the contractor. If the number of trees to be pruned grows, so does the total lump sum I must pay. He also uses the same approach to compute the percent cumulative complete." Discussion items a. Is the method Mr. Volts refers to EVA? b. What is the official formula in EVA that Mr. Volts is using to calculate "the sum I cumulatively pay/owe the contractor"? c. Discuss how Mr. Voltage can calculate schedule variance and cost variance.