Let us assume the total sales of the local Subway = x
Then
Total sales done by cash at the local Subway = x/9
Total cash sales for the week at the local Subway = $690
Then
x/9 = 690
x = 690 * 9
= 6210 dollars
From the above deduction, it can be easily concluded that the total sales of the local Subway was $6210. I hope that the procedure is clear enough for you to understand.