Answer:
<u>A hot-dog costs $ 3.50 and a cheeseburger costs $ 5</u>
Step-by-step explanation:
1. Let's review the information given to us to answer the question correctly:
Mrs Perez purchase: 3 hot-dogs and 3 cheeseburgers for $25.50
Mr Perez purchase: 6 hot-dogs and 4 cheeseburgers for $41.00
2. How much does a hot-dog cost? How much does a cheeseburger cost?
Let's write our system of equations, this way:
x = Cost of a hot-dog
y = Cost of a cheeseburger
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3x + 3y = 25.50
6x + 4y = 41
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3x + 3y = 25.50
3x = 25.5 - 3y
x = 8.5 - y (dividing by 3 at both sides)
Substituting x in the 2nd equation and solving for y:
6 (8.5 - y) + 4y = 41
51 - 6y + 4y = 41
-2y = 41 - 51 (subtracting 51 at both sides)
-2y = -10
y = -10/-2 = 5
Solving for x in the 1st equation:
3x + 3y = 25.5
3x + 3 (5) = 25.5
3x + 15 = 25.5
3x = 25.5 -15 (subtracting 15 at both sides)
3x = 10.50
x = 10.50/3 = 3.50
<u>A hot-dog costs $ 3.50 and a cheeseburger costs $ 5</u>
