Question $12$: The Four Step Process

The table shows the activity cycle times and staffing for the four steps. Suppose the steps in activity D are made easier, so the activity time per unit in step D is reduced by $50\%($to $0\mathrm{.}25$ min per unit$).$ If the assignment of workers to steps remains the same, by how much does the capacity of the entire process increase in units per min? $($Note: the activity cycle time are per worker. So$,$ if the number of workers is greater than $1,$ the output at the corresponding step will require proportionately less time.$)$