Answer:
90 and 30 liters
Step-by-step explanation:
1) if solution of 20% is 'x' and of 60% is 'y' liters, then
2) the pure chlorine is: for solution of 20% - 0.2x, for solution of 60% - 0.6y and
3) the mix of the two solutions is 120=x+y.
4) using these items it is possible to make up the system of two equations:
5) finally, x=90 liters of 20%; y=30 liters of 60% solution.
Answer:
And we can find this probability with the following difference:
And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.
Step-by-step explanation:
Previous concepts
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 Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the number of gallons of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with the following difference:
And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.