Answer: the price of one taco is $2.5
Explanation:
Let x represent the price of one taco.
Let y represent the price of one burritos.
Melissa purchased 4 tacos and 2 burritos and her total was $21. This means that
4x + 2y = 21- - - - - - - - - - - - - -1
Casey purchased 4 tacos and 3 burritos and her total was $26.50. This means that
4x + 3y = 26.5- - - - - - - - - - - - - -1
Subtracting equation 2 from equation 1, it becomes
- y = - 5.5
y = 5.5
Substituting y = 5.5 into equation 1, it becomes
4x + 2 × 5.5 = 21
4x + 11 = 21
4x = 21 - 11
4x = 10
x = 10/4
x = 2.5