Find the cost of goods sold if sales total $$78,645$ for the inventory table shown below.

$\backslash$table$[[$Date of purchase,$\backslash$table$[[$Units$],[$purchased$]],\backslash$table$[[$Cost per$],[$unit$]],$Total cost,$\backslash$table$[[$Retail price$],[$per unit$]],\backslash$table$[[$Total retail$],[$value$]]],[$Beginning inventory,$40,$$$860,$$$34,400,$$$985,$$$39,400$