Build the mathematical proof for Leach’s solution (p. 110) that concentrating contingency results in shorter

Build the mathematical proof for Leach’s solution (p. 110) that concentrating contingency results in shorter project durations due to the difference between: The sum of the squares of the individual variation for each task, andThe sum of the square root of the sum of the squares of the amount of safety removed from each task.page109-11 1)pdf