Can someone show me how to do this problem? steps with explanations please

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What is the minimum cost of crashing the following project that Roger Solano manages at Slippery Rock University by 4 days? Normal Crash Time Activity Time (days) (days) A 6 5 Normal Cost B 8 6 Total Cost Immediate with Crashing Predecessor(s) $1,100 $400 $650 $1,500 . $1,650 C 5 4 $800 $300 $600 $750 $1,200 C D 6 3 E 6 4 By how many days should each activity be crashed to reduce the project completion time by 4 days? Fill in the table below. (Enter your responses as whole numbers.) Each Activity Should be Reduced BY (days) Activity A B D E The total cost of crashing the project by 4 days is $ . (Enter your response as a whole number.)