Answer:
A) 0.05
Step-by-step explanation:
Let's summarize into an equation the information we can get from that table.
We have 4 liters of an acid of an unknown concentration, let's call it (4x).
We have 10 liters of an acid with known concentration of 0.40.
And we have a total of 14 liters overall with a concentration of 0.3o.
That's like a weighted average formula: 4x + 10 y = 14z
Let's replace the concentration values we know and solve this:
4x + 10 (0.4) = 14 * 0.3
4x + 4 = 4.2
4x = 0.2
x = 0.05
So, the concentration of the 4 liters of acid on concentration X are in fact of concentration of 0.05.
Answer:
22 days
Step-by-step explanation:
55 divided by 2.5=22 days
Answer:
four n squared divided by 7
Step-by-step explanation:
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Answer: The number of first-year residents she must survey to be 95% confident= 263
Step-by-step explanation:
When population standard deviation (
) is known and margin of error(E) is given, then the minimum sample size (n) is given by :-
, z* = Two-tailed critical value for the given confidence interval.
For 95% confidence level , z* = 1.96
As, = 8.265, E = 1
So, ![n= (\dfrac{1.96\times8.265}{1})^2 =(16.1994)^2\\\\= 262.42056036\approx263\ \ \ [\text{Rounded to the next integer}]](https://tex.z-dn.net/?f=n%3D%20%28%5Cdfrac%7B1.96%5Ctimes8.265%7D%7B1%7D%29%5E2%20%3D%2816.1994%29%5E2%5C%5C%5C%5C%3D%20262.42056036%5Capprox263%5C%20%5C%20%5C%20%5B%5Ctext%7BRounded%20to%20the%20next%20integer%7D%5D)
Hence, the number of first-year residents she must survey to be 95% confident= 263
