Question

2 sandwiches and 1 drink is $10.00. 1 sandwich and 2 drinks is $8.00. how much is each sandwich?

Answer 1

2s + d = 10....multiply by -2
s + 2d = 8
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-4s - 2d = -20 (result of multiplying by -2)
s + 2d = 8
---------------add
-3s = - 12
s = -12/-3
s = 4 <=== cost per sandwich