Answer:
A pound of potato costs $3.10
A dozen egg costs $5.5
A wheel of cheese costs $6.25
Step-by-step explanation:
Represent
- a dozen egg with D
- a wheel of cheese with W
- a pound of potato with P
For Adam:
[tex]3D + W + 5P = 38.25[/tex] ---- (1)
For Barry:
[tex]D + 10P = 36.50[/tex] ---- (2)
For Charles:
[tex]2D + 2P = 17.20[/tex] ---- (3)
Make D the subject in (2)
[tex]D = 36.50 - 10P[/tex]
Substitute 36.50 - 10P for D in (3)
[tex]2(36.50 - 10P) + 2P = 17.20[/tex]
[tex]73 - 20P + 2P = 17.20[/tex]
[tex]73 - 18P= 17.20[/tex]
Collect Like Terms
[tex]- 18P= 17.20 - 73[/tex]
[tex]- 18P= -55.8[/tex]
[tex]18P= 55.8[/tex]
Solve for P
[tex]P = 55.8/18[/tex]
[tex]P = 3.1[/tex]
Substitute 3.1 for P in [tex]D = 36.50 - 10P[/tex]
[tex]D=36.50 - 10 * 3.1[/tex]
[tex]D=36.50 - 31[/tex]
[tex]D=5.5[/tex]
Substitute 3.1 for P and 5.5 for D in [tex]3D + W + 5P = 38.25[/tex]
[tex]3(5.5) + W + 5(3.1) = 38.25[/tex]
[tex]16.5 + W + 15.5 = 38.25[/tex]
Solve for W
[tex]W = 38.25 - 16.5 - 15.5[/tex]
[tex]W = 6.25[/tex]