Question

Two cartons of milk and one sandwich costs $3.00, and two sandwiches cost $4.20 without milk. Find the cost of one carton of milk.

Answer 1

Answer:

$0.45 or 45 cents

Step-by-step explanation:

Let x = carton of milk

     y = sandwich

2x + y = 3

2y = 4.2

Let's use the substitution method to solve this

First, divide both sides by 2 in the second equation

2y/2 = 4.2/2

y = 2.1

Substitute the new y into the first equation

2x + 2.1 = 3

Now subtract 2.1 from both sides

2x + 2.1 = 3

     - 2.1   - 2.1

2x = 0.9

Divide both sides by 2 to isolate the x variable

2x/2 = 0.9/2

x = 0.45