Respuesta :
Answer:
The D cells are worth $2.20, and the C cells are worth $1.90.
Step-by-step explanation:
This can be written as:
4x + 2y = 12.60
6x + 4y =20.80
Our goal is to find one variable, then use that information to find the other.
If we multiply the top function by -1.5, we get:
-6x - 3y = -18.90
We can add this to the previous equation.
-6x - 3y = -18.90
+ 6x + 4y = 20.80
--------------------------
y = 1.90
The C cells are worth $1.90.
Plug this value into one of the other equations and solve for x.
4x + 2y = 12.60
4x + 2(1.90) = 12.60
4x + 3.80 = 12.60
4x = 8.80
x = 2.20
The D cells are worth $2.20.
Check these values in the other equation.
6x + 4y = 20.80
6(2.20) + 4(1.90) = 20.80
13.20 + 7.60 = 20.80
20.80 = 20.80
Answer:
C = $1.90 each
D = $2.20 each
Step-by-step explanation:
Given:
Power pack A: 4D + 2C = 12.60
Power pack B: 6D + 4C = 20.80
Isolate any one variable:
4D + 2C = 12.60
4D = 12.60 - 2C
D = 3.15 - 0.5C
Substitution to find cost of C cell battery:
6D + 4C = 20.80
6(3.15 - 0.5C) + 4C = 20.80
18.9 - 3C + 4C = 20.80
18.9 + C = 20.80
C = 1.90
Substitution to find cost of D cell battery:
4D + 2C = 12.60
4D + 2(1.90) = 12.60
4D + 3.8 = 12.60
4D = 8.8
D = 2.20
