Answer:
Amount of 5% solution = 5.7 Litres
Amount of 40% solution = 4.3 Litres
Step-by-step explanation:
First, of all, let x be the amount of 5% solution used
Since, the scientist needs 10 L of solution, then;
Let 10 - x be the amount of 40% solution used
Now, we are told that she needs 10 L of a 20% acid solution.
This means that;
5%x + 40%(10 - x) = 20%(10).
Simplifying this gives;
0.05x + 0.40(10 - x) = 0.20 × 10
Expanding the bracket gives;
0.05x + 4 - 0.4x = 2
0.4x - 0.05x = 4 - 2
0.35x = 2
x = 2/0.35
x ≈ 5.7 litres
Thus, she will need to mix 5.7 liters of the 5% solution.
Since 10 - x be the amount of 40% solution used , then;
the amount of 40% solution = 10 - 5.7 = 4.3 litres
Answer:
And rounded up we have that n=2663
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The population proportion have the following distribution
Solution to the problem
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 99% of confidence, our significance level would be given by 
and 
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that 
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
We can assume an estimated proportion of 
since we don't have prior info provided. And replacing into equation (b) the values from part a we got:
And rounded up we have that n=2663
Answer:
Area = 2(5x - 4) + 2(5x)
Step-by-step explanation:
Perimeter is the sum of twice the width and twice the length of the rectangle. And since the question is asking us for an equation, we need to write, Area = 2(5x - 4) + 2(5x). When you are required to find the value of x with a given area, just plug that area into the equation, distribute, and simplify to get x.
When converting to a fraction u multiply 66*3 getting 198 and u add the numerator getting 200 you u keep the demomenator which is 3 so 66and 2/3 is 200/3.
Answer:
50
Step-by-step explanation:
The value of x is 50 degrees
bcoz it is isosceles triangle
so two angles are equal
so value of x is 50
I hope this will help u
