2 ways
1 calcluls
2. algebra
calculus, just take the deritivive and find wher it is 0
y=-0.2x+10
at x=50
sub 50 for x in original
y=250
algebra
for
y=a(x-h)²+k
(h,k) is vertex
k is maximum value
complete the square
y=(-0.1x²+10x)
y=-0.1(x²-100x)
take 1/2 of -100 and square it and add negative and positive inside
-100/2=-50, (-50)²=2500
y=-0.1(x²-100x+2500-2500)
factor perfect square
y=-0.1((x-50)²-2500)
exand
y=-0.1(x-50)²+250
vertex at (50,250)
producing 50 units yeilds a sale price of $250
max price is $250
It is $2.25 for 1 pound of apples and $9 for 4 pounds of apples
Answer:
Is this really true?
Are you talking bout the people that put those links as answers?
Step-by-step explanation:
1. 2/7x100=28.57%
2.3:7x100=42.85%
3.1/7x100=14.29%
4. 6/7x100=85.71%
5.0%
6.4/7x100=57.14%
Good luck!
Let's say we'll mix "x" amount of the 80% solution, how much antifreeze is in it? well is just 80% of antifreeze, and the rest is something else.... what's 80% of "x"? so is (80/100)*x, or 0.8x.
likewise, the mixture will be a 70% solution, and let's say it adds up to "y" amount, so how much antifreeze is in it? well (70/100) * y or 0.7y.
![\bf \begin{array}{lccclll} &\stackrel{gallons}{amount}&\stackrel{\%}{quantity}&\stackrel{antifreeze}{quantity}\\ &------&------&------\\ \textit{80\% sol'n}&x&0.80&0.8x\\ \textit{10\% sol'n}&100&0.10&10\\ ------&------&------&------\\ mixture&y&0.70&0.7y \end{array}](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Barray%7D%7Blccclll%7D%0A%26%5Cstackrel%7Bgallons%7D%7Bamount%7D%26%5Cstackrel%7B%5C%25%7D%7Bquantity%7D%26%5Cstackrel%7Bantifreeze%7D%7Bquantity%7D%5C%5C%0A%26------%26------%26------%5C%5C%0A%5Ctextit%7B80%5C%25%20sol%27n%7D%26x%260.80%260.8x%5C%5C%0A%5Ctextit%7B10%5C%25%20sol%27n%7D%26100%260.10%2610%5C%5C%0A------%26------%26------%26------%5C%5C%0Amixture%26y%260.70%260.7y%0A%5Cend%7Barray%7D)
so whatever "x" is, we know that
x + 100 = y.
and we know that
0.8x + 10 = 0.7y.