Answer:
i cant see it
Step-by-step explanation:
Answer:
the answer is .875
Step-by-step explanation:
u were close!! keep trying
You must develop a cost function C(x) and then minimize its value.
How much dwill the glass cost? It's $1 per sq ft, and the total area of the glass is 4(xh), where x is the length of one side of the base and h is the height of the tank. The area of the metal bottom is x^2, which we must multiply by $1.50 per sq ft.
This cost function will look like this: C(x) = 4($1/ft^2)xh + ($1.50/ft^2)x^2
but we know that (x^2)h= 6 cu ft, or h = (6 cu ft) / (x^2). Subst. this last result into the C(x) equation, immediately above:
C(x) = 4($1/ft^2)x[6 ft^3 / x^2] + ($1.50/ft^2)x^2
Let's focus on the numerical values and ditch the units of measurement for now:
C(x) = 4x(4/x^2) + 1.50x^2, or
C(x) = 16/x + 1.5x^2
Differentiate this with respect to x:
C '(x) = -16 / x^2 + 3 x
Set this equal to 0 and solve for x: -16/x^2 = -3x, or 16 = 3x^3
Then x^3 = 16/3, and x = 5 1/3 ft. We already have the formula
(x^2)h= 6 cu ft, so if x = 5 1/3, or 16/3, then (16/3)^2 h = 6, or
h = 6 / [16/3]^2.
h = 6 (9/256) = 0.21 ft. While possible, this h = 0.21 ft seems quite unlikely.
Please work through this problem yourself, making sure you understand each step. If questions arise, or if you find an error in my approach, please let me know.
Once again:
1. Write a formula for the total cost of the material used: 4 sides of dimensions xh each, plus 1 bottom, of dimensions x^2. Include the unit prices: $1 per square foot for the sides and $1.50 per square foot for the bottom.
2. Differentiate C(x) with respect to x.
3. Set C '(x) = 0 and solve for the critical value(s).
4. Calculate h from your value for x.
5. Write the dimensions of the tank: bottom: x^2; height: h
Total throws = 187
Let three throws = 3t
And
Seven throws = 7s
So
3t + 7s = 187 -------------- (1)
While total collected money = $57
Money for three throws = 1t
Money for seven throws = 2s
Hence
1t +2s = 57 ------------------(2)
Now solving both equations, so multiply second
equation by 3 and subtract it from equation (1);
Equation (2) becomes 3t + 6s = 171
While subtracting it from equation (1) gives the
final equation as below.
s = 16
Putting s = 16 in equation (2);
1t + (2x16) = 57
1t + 32 = 57
t = 25
Thus 25 people bought three throws and 16 people
bought seven throws.
As for 25 people having three throws = $25
And
16 people having seven throws = 2x16 = $32
So total earned money = 25 + 32 = $57
<span>Hence proved. </span>
Answer:
11.57
Step-by-step explanation:
We have a simple formula to solve this:
where
SS is sum of squares
s^2 is the variance, and
n is the number of data points
We are given all the info to find out s^2. Hence,
