This is Chapter 9, Exercise 1 in the Project Management: The Managerial Process 8e Edition book on Page 447. This is all the complete information I got from this question so I need to know how to approach this and answer correctly.

Use the following information to compress one time unit per move using the least-cost method. Reduce the schedule until you reach the crash point of the network. For each move identify what activity or activities were crashed and the adjusted total cost. Note: The correct normal project duration, critical path, and total direct cost are provided.

Crash Cost (slope) Maximum Crash Time Normal Time Normal Cost MmO O m e 5 50 100 60 60 70 O o= P N = - L W W ES2888% Total direct cost: $1.000