Given is the Rate of each hamburger = 2.10 dollars each.
The number of hamburgers that we sell = 3 hamburgers.
Charges for all 3 hamburgers = 3 x 2.10 = 6.30 dollars.
Tax charged on these 3 hamburgers = 0.38 dollars.
Total Bill = Charges for 3 hamburgers + Tax
Total Bill = 6.30 + 0.38 = 6.68 dollars.
Customer paid = 10 dollars.
The amount to be returned to customer = Bill paid by customer - Total Bill charged = 10 - 6.68 = 3.32 dollars.
Hence, the customer would get a change of 3.32 dollars.