Answer:
Option C = 15
Step-by-step explanation:
In principle when a function <em>f(x) </em>varies directly with <em>x</em> it suggests that any changes in x results in the equivalent changes in<em> f(x)</em>. If we have two variables, i.e. <em>y</em> representing<em> f(x)</em> and <em>x</em> representing itself, any increment/decrement in <em>x</em> will result to the same increment/decrement in <em>y</em> by a factor <em>a, thus we can say that y = ax, implying y and x have the same ratio. </em>
In the given question we know that <em>
</em> when
<em>, </em>which translates as

This tells us that
varies by a factor (lets call it)
for a given value of
.
To find this factor we can just divide 45 with 9 which gives: 
Thus the factor
here is
which finally tells us that
Eqn (1) our original function.
Since we now know our function we can plug in the value for
and solve for
as follow:



Looking at the given options in the question we can conclude that the correct answer is Option C = 15
Can you please explain this a bit better? i dont understand
ok so lets start of with the fact that the whole thing is 21 units.
So we do 21-9=12 so then we now know that the rectangle is 12 so then we do 12*8 units which is= 96 . Now the triangles. so the first one we know that its 8*3 and times it by 1/2 because two triangles is equal to a rectangle so the first triangle is 12 and now the second. its 9-3= 6 then its 6*8*1/2 which is equal to 24 so now the final answer is
96+12+24 which is equal to 132 so i'm guessing it 132 square units
Answer: 95% confidence interval for the difference between the proportions would be (1.31, 1.39).
Step-by-step explanation:
Since we have given that
Number of alluvial wells = 349
Number of quaternary wells = 143
Number of alluvial wells that had concentrations above 0.1 = 182
Number of quaternary wells that had concentrations above 0.1 = 112
Average of alluvial wells = 0.27
Standard deviation = 0.4
Average of quaternary wells = 1.62
Standard deviation =1.70
So, 95% confidence interval gives
alpha = 5% level of significance.

So, 95% confidence interval becomes,

Hence, 95% confidence interval for the difference between the proportions would be (1.31, 1.39).