This problem is mainly concerned with setting up an equation.
let's add the interest rates times their respective investment amounts:



simplify:

sum of interest:

1780 = (9000+x) 0.10 + x 0.06 + (11000-2x)0.08


solution:
He does not have any invested in the 6%, while he has 9000 invested at 10% and 11,000 invested at 8%
to check:


So this ended up being a trick problem because he does not actually have any invested in the 6% option.
72 days
there are 720 ounces total (convert 45 pounds to 720 ounces)
divide that by the 10 ounces per day and get 72 days
We can let the radius of the semi circles be r and x can be the length of the rectangle.
The perimeter will be Perimeter = 2x + 2pr = 1200
The area of the rectangle is Area = x(2r)
Once we solve the perimeter equation, you get x = 600.
Put this into the area equation and you get Area = (600 - pr)(2r)
The maximum then gives r = 95. 493 and area 57, 295.8
Dimensions
Height is twice the radius or 190.986. Find base use equation x = 600 - p(95.493) = 300.
This means dimensions are 300 by 190.986
Answer: CORRECT
Step-by-step explanation: Because any negative number will be positive when multiplied together but since there are 3 negative number the 3rd negative will always negate the positive so therefore Delila is correct