Answer: choice A. 40 liters
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Explanation:
x = number of liters of the 50% alcohol solution
If we have x liters of 50% alcohol, then we have 0.50*x liters of pure alcohol. This is added to 0.90*40 = 36 liters of pure alcohol (from the 90% solution).
So far we have 0.50*x + 36. This expression represents the total amount of pure alcohol. We want a 70% solution, so we want 70% of the total 40+x meaning 0.50*x + 36 is to be set equal to 0.70*(40+x) and we solve for x as shown below
0.50*x + 36 = 0.70*(40+x)
0.50*x + 36 = 0.70*(40)+0.70*(x)
0.50*x + 36 = 28+0.70*x
36 - 28 = 0.70*x - 0.50x
8 = 0.20x
0.20x = 8
x = 8/0.20
x = 40
So that is why the answer is choice A. 40 liters
168
You add 4, 1, and 2 to get 7. You put 4/7=x/294. Then you use proportions to solve for x.
7x=1176
x=168
Answer:
3: 2q − 4 = 20
Step-by-step explanation:
Solve for q:
2 q - 4 = 20
Add 4 to both sides:
2 q + (4 - 4) = 4 + 20
4 - 4 = 0:
2 q = 20 + 4
20 + 4 = 24:
2 q = 24
Divide both sides of 2 q = 24 by 2:
(2 q)/2 = 24/2
2/2 = 1:
q = 24/2
The gcd of 24 and 2 is 2, so 24/2 = (2×12)/(2×1) = 2/2×12 = 12:
Answer: q = 12
I think it's 85 but Is this like a multiple choice question?
