What Is the Minimum Cost Completion Time for This Project

What is the minimum cost completion time for this project if the activities have normal and crash costs as indicated and there is a $1,000 fixed cost for each day on site plus a $500 penalty for each activity that is crashed? The crash costs represent the cost of a fully expedited activity.For example,reducing activity Y from 13 days to 12 days costs an extra $100 on top of the $500 expediting cost for a total cost of $2,600.Reducing Y from 13 days to 10 days costs an extra $300 on top of the $500 expediting cost,for a total activity cost of $2,800.
$\begin{array}{|l|l|l|l|l|l|}\hline&&\text { Normal } & \text {Normal }& \text {Crash}\\ \text { Activity} & \text { Predecessor } & \text {Time } & \text { Cost } & \text { Time } & \text { Crash Cost }\\ \hline\mathrm{ Z} & & 2 & \$ 2,000 & 2 & \$ 2,000 \\\hline \mathrm{Y} & & 13 & \$ 2,000 & 10 & \$ 2,300 \\\hline \mathrm{X} & & 19 & \$ 2,000 & 15 & \$ 3,000 \\\hline \mathrm{W} & \mathrm{Z} & 18 & \$ 2,000 & 15 & \$ 3,000 \\\hline \mathrm{V} & \mathrm{X} & 10 & \$ 2,000 & 9 & \$ 3,000 \\\hline \mathrm{U} & \mathrm{Y} & 13 & \$ 2,000 & 11 & \$ 3,000 \\\hline \mathrm{T} & \mathrm{W} & 18 & \$ 2,000 & 14 & \$ 4,000 \\\hline \mathrm{S} & \mathrm{V} & 4 & \$ 2,000 & 3 & \$ 3,000 \\\hline \mathrm{R} & \mathrm{U} & 6 & \$ 2,000 & 5 & \$ 3,000 \\\hline\mathrm{Q} & \mathrm{R}, \mathrm{S} & 15 & \$ 2,000 & 13 & \$ 3,000 \\\hline \mathrm{P} & T & 13 & \$ 2,000 & 12 & \$ 3,000 \\\hline \mathrm{N} & \mathrm{P}, \mathrm{Q} & 4 & \$ 2,000 & 4 & \$ 2,000\\\hline \end{array}$