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
Answer:
C
Step-by-step explanation:
Area = π
r means radius
radius = d/2
d = diameter
8 /2 = 4
4 is radius
= 16
^ ( its 4 x 4 ) ^
so then,
Area = 16π
Answer:
450 cm^3
Step-by-step explanation:
( 1/2 (5+7.5) 6 ) 12
2/3 to 8 is the same ratio if we multiply both sides by 3/2 so:
2/3×3/2=1
8×3/2=12
So 1 to 12
Answer:
3 times 4 over 5 equals 2.4
Step-by-step explanation:
