The cost of 6 sandwiches and 4 drinks is $53. The cost of 4 sandwiches and 6 drinks is $47 how much does one sandwich cost

Let sandwiches and drinks be s and d resp so according to the question,

by 1st case,

6s + 4d = 53

or, d = (53-6s) / 4

again by 2nd case,

4s + 6 d = 47

4s + 6 (53-6s) / 4 = 47

or, (8s + 159-18s) / 2=47

or 159-10s = 94

or 65 = 10s

or, s = $6.5