Problem $2$

Dr$.$ Gold, a mad scientist, has identified the ten steps required to create a race of atomic supermen to complete his plans for world conquest. The estimated time in weeks and cost in US dollars appear in the table along with the shortest possible duration for each activity and cost of those expedited activities. Activities are designated generically as A$,$ B$,$ and so on in order to avoid any copycat projects of this nature.

What is the minimum number of days to complete this project?

What activities would Dr$.$ Gold crash and what would the cost be to get the project completed in $50$ days?