Okay, we heve this:
Total Bill: $920*10=$9200
The proce after the first dicount is: $9200*80%=$7360
After this he received an additional 7% discount, so: $7360*93%=$6844.8
They pay within the cash discount period, so they get an additional 3% discount (3/10): $6844.8*97%=$6639.46.
The che