Answer:
75 square feet
Step-by-step explanation:
The aquarium is designed to hold 62.5cubic feet
Since the aquarium has a square base, assume the aquaruim is a square prism
Let X be the lenght
Let y be the height
x^2.y = 62.5
y = 62.5x^2
The area of each side of the aquarium is xy. Since there are four sides, the total area of the side= 4xy
The area of the bottom of the aquarium = x^2
Total surface area = 4xy + x^2
Put y = 62.5/x^2 into the total surface area equation
A = 4x(62.5/x^2) + x^2
A= 250/x + x^2
Differentiate A with respect to x
dA/dx = -250(x^-2) + 2x
dA/dx = 0
0 = 2x - 250x^-2
2x = 250x^-2
2x =250/ x^2
2x^3 = 250
x^3 = 250/2
x^3 = 125
x = cbrt (125)
x = 5
Put x= 5 into A = x^2 + 250x^-1
A= 5^2 + 250(5^-1)
A= 25 + 250/5
A = 25 + 50
A = 75 square feet
Answer:
Greater
Step-by-step explanation:
A number must be greater that a small percentage of the number
Greater
---------------------
45% = 0.45
.45 x = 45
Divide both sides by .45
x = 100
Difference in doughnuts = 50 - 40 = 10
Difference in money = 15 + 5 = 20
20 ÷ 10 = $2
Each doughnut costs $2
<em>Check:</em>
40 x 2 + 5 = $85
50 x 2 -15 = $85
Ravi has $85 at first.
Each doughnut costs $2
10 800 0 to the first problem
The first one is 17 13/15 the second one is 22 1/20
