Problem 4 For the project in Problem 2, normal time (in minutes) and normal cost ($), and crash time (in minutes) and crash cost ($) is given for each task as follows: TASK NORMAL NORMAL TIME A 15 15 B 25 20 30 300 350 D 15 150 12 200 E 15 150 12 200 20 200 15 300 H 10 500 10 500 a. Formulate an appropriate crashing model to achieve a completion time of 48 minutes. (10 points) b. Use Excel to determine which tasks should be shortened to achieve this goal and by how much? (6 points) c. How much will it cost to achieve this goal? (3 points)