Answer:

Step-by-step explanation:
we are given
y varies directly as x
so, we can write equation as

where
k is constant of proportionality
We have
at x=-1 , y=6
so, we can use it to find k

so, we get

now, we can plug it back

now, we can plug x=5
and we get


So, first lets define our variables:
let x = the number of dimes
let y = the number of nickels
so our first equation would be x+y = 16
Since dimes are 10 cents and nickels are 5 cents the next equation would be as follows:
.10x+.05y = 1.35
now change the first equation so y = -x+16
now substitute:
.10x+.05(-x+16) = 1.35
then multiply so you get .10x+-.05x+0.8=1.35
combine like terms and you get .05x+0.8 = 1.35
then subtract 0.8 from both sides and you get .05x = 0.55 then subtract
and you get x = 11 then substitute 11 for where x should be and you should get y = 5
So, you have 11 dimes and 5 nickels
Answer:
2.5x+0.75y=933
x+y=747
Step-by-step explanation:
x= number of cheese sandwiches
y= number of soft drinks
first equation: 2.5x+0.75y=933
**this is representing the cost of the drinks and sandwiches
second equation: x+y=747
**because x and y are the NUMBER of soft drinks and sandwiches, they both have to toal up to 747.
Answer:
The standard deviation of the data set is
.
Step-by-step explanation:
The Standard Deviation is a measure of how spread out numbers are. Its symbol is σ (the greek letter sigma)
To find the standard deviation of the following data set

we use the following formula

Step 1: Find the mean
.
The mean of a data set is the sum of the terms divided by the total number of terms. Using math notation we have:


Step 2: Create the below table.
Step 3: Find the sum of numbers in the last column to get.

Step 4: Calculate σ using the above formula.

Answer:
The value is 
Step-by-step explanation:
From the question we are told that
The area of the rectangular pen is 
The cost of material used to make one side is 
The cost of material used to make the other sides is 
Now , the fence to be build around the rectangular pen has four sides, the first opposite sides are equal, let assume each of the to be x yard and the other opposite sides are also equal as well let assume of the to be y yard
So the cost is mathematically represented as

=> 
=> 
Now the area of the fence is mathematically represented as

=> 
=> ![C = 9x + 6[\frac{24}{x} ]](https://tex.z-dn.net/?f=C%20%3D%20%20%209x%20%20%2B%20%206%5B%5Cfrac%7B24%7D%7Bx%7D%20%5D)
=> ![C = 9x + [\frac{144}{x} ]](https://tex.z-dn.net/?f=C%20%3D%20%20%209x%20%20%2B%20%20%5B%5Cfrac%7B144%7D%7Bx%7D%20%5D)
Now differentiating


At minimum 
So




Now substituting for x in the equation above to obtain minimum cost
![C = 9(5.66) + [\frac{144}{5.66} ]](https://tex.z-dn.net/?f=C%20%3D%20%20%209%285.66%29%20%20%2B%20%20%5B%5Cfrac%7B144%7D%7B5.66%7D%20%5D)
