Equivalent Units of Materials Cost

The Rolling Department of Jabari Steel Company had $5,100$ tons in beginning work in process inventory $(10\%$ complete$)$ on October $1.$ During October, $84,500$ tons were completed. The ending work in process inventory on October $31$ was $4,200$ tons $(80\%$ complete$).$

What are the total equivalent units for direct materials for October if materials are added at the beginning of the process? units