

- Customer 1 bought 2 hamburgers and 4 drinks at a cost of $13.00
- Customer 2 bought 3 hamburgers and 7 drinks at a cost of $21.00

- We have to find the total cost of 8 drinks and 9 hamburgers

Let the cost of hamburgers and drinks be x and y
According to the question,


Solving eq( 1 ) we get :-



Subsituting eq(3) in eq( 2 ) :-






Subsituting value of y in eq(3) :-




Therefore,




And




Total cost of the 8 drinks and 9 hamburgers


Hence, The total cost paid by you for 8 drinks and 9 hamburgers is $43.50 .