Respuesta :
Step-by-step explanation:
Let's say x is the amount of $2.70/lb coffee and y is the amount of $3.20/lb coffee.
The total amount is:
x + y = 400
The total worth is:
2.70x + 3.20y = 3.00×400
2.7x + 3.2y = 1200
Solving the system of equations through substitution:
x = 400 - y
2.7 (400 - y) + 3.2y = 1200
1080 - 2.7y + 3.2y = 1200
0.5y = 120
y = 240
x = 160
The grocer uses 160 pounds of the $2.70/lb coffee and 240 pounds of the $3.20/lb coffee.
By solving a system of equations, we will see that they used 240 pounds of the $3.20 coffee and 160 pounds of the $2.70 coffee.
How to find the system of equations?
First, we need to define the variables, we can use:
- x = pounds of the $2.70 coffee used.
- y = pounds of the $3.20 coffee used.
We know that they make 400 pounds of the mixture, then:
x + y = 400
We also know that the price of the mixture is $3.00 per pound, then we will have that:
x*$2.70 + y*$3.20 = 400*$3.00
So the system of equations is:
x + y = 400
x*$2.70 + y*$3.20 = 400*$3.00
To solve this, we isolate one of the variables in one of the equations. For example, I will isolate x on the first equation:
x = 400 - y
Now we can replace that on the other equation to get:
(400 - y)*$2.70 + y*$3.20 = 400*$3.00
And solve this for y.
400*$2.70 - y*$2.70 + y*$3.20 = 400*$3.00
y*$0.50 = 400*$3.00 - 400*$2.70 = 400*$0.30
y = ( 400*$0.30)/$0.50 = 240
Then we have:
x = 400 - y = 400 - 240 = 160
This means that they used 240 pounds of the $3.20 coffee and 160 pounds of the $2.70 coffee.
If you want to learn more about systems of equations, you can read:
https://brainly.com/question/13729904