It’s b because if Mandy goes 18 days and her friend goes 3 times the days she goes.
Answer:
- Walnuts cost $1.75, chocolate chips cost $2.75
Step-by-step explanation:
<h3>Let the costs be:</h3>
- Walnuts - x
- Chocolate chips - y
<h3>Set equations as per question</h3>
For 7 pounds of walnuts and 9 pounds of chocolate chips, the total cost is $37:
For 5 pounds of walnuts and 3 pounds of chocolate chips, the total cost is $17:
<h3>Solve the system by elimination</h3>
Multiply the second equation by 3 and subtract the first equation, solve for x:
- 3(5x + 3y) - (7x + 9y) = 3(17) - 37
- 15x + 9y - 7x - 9y = 51 - 37
- 8x = 14
- x = 14/8
- x = 1.75
Find the value of y:
- 7*1.75 + 9y = 37
- 12.25 + 9y = 37
- 9y = 37 - 12.25
- 9y = 24.75
- y = 24.75/9
- y = 2.75
Amma solve it first then ill tell you what i got as the answer:)
Answer:
- y = 81-x
- the domain of P(x) is [0, 81]
- P is maximized at (x, y) = (54, 27)
Step-by-step explanation:
<u>Given</u>
- x plus y equals 81
- x and y are non-negative
<u>Find</u>
- P equals x squared y is maximized
<u>Solution</u>
a. Solve x plus y equals 81 for y.
y equals 81 minus x
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b. Substitute the result from part a into the equation P equals x squared y for the variable that is to be maximized.
P equals x squared left parenthesis 81 minus x right parenthesis
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c. Find the domain of the function P found in part b.
left bracket 0 comma 81 right bracket
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d. Find dP/dx. Solve the equation dP/dx = 0.
P = 81x² -x³
dP/dx = 162x -3x² = 3x(54 -x) = 0
The zero product rule tells us the solutions to this equation are x=0 and x=54, the values of x that make the factors be zero. x=0 is an extraneous solution for this problem so ...
P is maximized at (x, y) = (54, 27).
