The following is a table of activisies associated with a project at Rafay Ishfaq's software firm in Chicago, their durations, what activises each must precede and the crash cost to reduce duration per week: Suppose that Rafay is only given 6 weeks (instead of 9 ) to complote the project. By how many woeks should each activity be crashed in order to meet the deadline? Assume that you can crash an activity down to O weeks duration. What is the total crashing cost? 4 (Enter your response as a whole number)