Lets call x the amount of 18% solution and y the amount of 40% solution, and write as equations the info of the problem:
18x + 40y = 10(20)
x + y = 10
lets multiply the second equation by -18 and add to the first:
18x + 40y = 200
-18x -<span> 18y = -180
</span>----------------------
0 + 22y = 20
y = 20/22 = 10/11
and substitute in the original equation:
x <span>+ y = 10
</span>x = 10 - y
x = 10 - 10/11
x = 110/11 - 10/11
x = 100/11
so they have to use 100/11 liters of 18% solution and 10/11 liters of 40% solution
Answer:
Plan II
Step-by-step explanation:
A certain county has 1,000 farms.
Corn is grown on 100 of these farms but on none of the others.
Since corn is grown on only 100 of these farms, the population of interest is the 100 farms on which corn is grown.
Therefore, a better method for estimating the total farm acreage of corn for the county is Plan II.
a) Identify the 100 corn-growing farms.
b) Sample 20 corn-growing farms at random.
c) Estimate the mean acreage of corn for corn-growing farms in a confidence interval.
d) Multiply both ends of the interval by 100 to get an interval estimate of the total.
Cannot be determined
<u>Explanation</u>
The probability cannot be determined because we do not know the distribution of the population. We also do not know the number of students who are taking marketing or spanish or total number of students. Since the data is incomplete, we cannot determine the probability of students taking spanish or marketing.
