Total = 36oz
Amount of 18% solution = x
Amount of 9% solution = 36 - x
Using the fact that (amount of solution) * (percent HCl) = amount HCl we can set up an expression for the amount HCl in a mixture of 18% and 9% solutions with a total volume of 36oz.
Amount of HCl = x*0.18 + (36 - x)*0.09
If we divide this by the amount of solution we get percent HCl, and we have a target of 10% HCl. Now we have an equation to solve,
[x*0.18 + (36 - x)*0.09]/36 = 0.1
x*0.09 + 3.24 = 3.6
.09x = 0.36
x = 4
Therefore,
4 ounces of 18% HCl solution and 32 ounces of 9% HCl solution
Check:
[(4*.18) + (.09*32)]/36 = 0.1?
0.1 = 0.1 Yes.
Answer:
In the Garden Club the cost will be a fixed fee of $25 and $10 for each rosebush, so if he buys X rosebushes, the total cost will be:
C1(X) = $25 + $10*X
While in the local nursery there is no initial cost, and each rosebush costs $15, so if he buys X rosebushes, the total cost will be:
C2(X) = $15*X
Now, let's find the value of X where C1 and C2 are equal, this is:
$25 + $10*X = $15*X
$25 = $15*X - $10*X = $5*X
X = 25/5 = 5
This means that if he buys 5 rosebushes, he will pay the same amount in both places.
If he buys less than 5 rosebushes, he will pay less in the local nursery (as it has a bigger slope, but no initial fee)
If he buys more than 5 rosebushes, he will pay less in the Garden club (because it has a smaller slope)
Plug in 2 for x. f(20=2-51 = -49
Area of rectangle is length x width
area of smaller rectangle
9x5=45
area of large rectangle
11x7=77
77-45=32
