SOLUTION: Ok one last time I will post the exact question I am having a difficult time with. Create a trail mix with only three ingredients (fruit, peanuts, cashews). You need to know the

Question 930381: Ok one last time I will post the exact question I am having a difficult time with.
Create a trail mix with only three ingredients (fruit, peanuts, cashews). You need to know the cost per pound and one ingredient must be twice the weight of the other two. Using systems of equations and/or matrices; how many pounds of each ingredient should be used to create a 140 lb mix that costs $6 per pound?
Answer by TimothyLamb(4379) (Show Source): You can put this solution on YOUR website!
x = pounds of peanuts
y = pounds of fruit
z = pounds of cashews
---
"one ingredient must have twice the weight of other two" ...
arbitrarily choose the weight of peanuts to be twice the sum of the weights of fruit and cashews:
x = 2(y + z)
---
sum of weights:
x + y + z = 140
---
sum of costs:
arbitrarily choose costs to reflect the actual market prices of these items:
...
peanuts = $1/lb
fruit = $2/lb
cashews = $20/lb
...
1x + 2y + 20z = 6*140
---
put the system of linear equations into standard form
---
x = 2y + 2z
x + y + z = 140
1x + 2y + 20z = 840
---
x - 2y - 2z = 0
x + y + z = 140
1x + 2y + 20z = 840
---
copy and paste the above standard form linear equations in to this solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
---
solution:
x = pounds of peanuts = 93.333333
y = pounds of fruit = 10.37037
z = pounds of cashews = 36.296296
---
check:
2*(10.37037 + 36.296296) = 93.33333
---
Solve and graph linear equations:
https://sooeet.com/math/linear-equation-solver.php
---
Solve quadratic equations, quadratic formula:
https://sooeet.com/math/quadratic-formula-solver.php
---
Solve systems of linear equations up to 6-equations 6-variables:
https://sooeet.com/math/system-of-linear-equations-solver.php
---
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