Max and Bob went to the store. Max bought 2 burgers and 2 drinks for $5.00. Bob bought 3 burgers and 1 drink for $5.50. How much is each burger and drink?
Set up the givens where b is the cost of a burger and d is the cost of a drink:
Max: 2b + 2d = 5
Bob: 3b + d = 5.50
Rearrange Bob's equation by subtracting 3b from each side
(3) d = 5.50 - 3b
Now substitute that d equation back into Max's Equation
2b + 2(5.50 - 3b) = 5
2b + 11 - 6b = 5
Combine b terms:
-4b + 11 = 5
Subtract 11 from each side
-4b = -6
Divide each side by -4
b = 3/2
b = $1.50
Now plug that back into equation (3):
d = 5.50 - 3(1.50)
d = 5.50 - 4.50
d = $1.00
Set up the givens where b is the cost of a burger and d is the cost of a drink:
Max: 2b + 2d = 5
Bob: 3b + d = 5.50
Rearrange Bob's equation by subtracting 3b from each side
(3) d = 5.50 - 3b
Now substitute that d equation back into Max's Equation
2b + 2(5.50 - 3b) = 5
2b + 11 - 6b = 5
Combine b terms:
-4b + 11 = 5
Subtract 11 from each side
-4b = -6
Divide each side by -4
b = 3/2
b = $1.50
Now plug that back into equation (3):
d = 5.50 - 3(1.50)
d = 5.50 - 4.50
d = $1.00