$20,000 is between $15,000 and $49,999, so we'll use the interest rate of 6.5% (see row 3)
r = 6.5% = 6.5/100 = 0.065
We'll use the decimal form of the interest rate as it is most common for financial math problems.
P = 20,000 is the amount deposited
t = 1 year is the amount of time
We will plug those values into the formula
i = P*r*t
to get the following:
i = P*r*t
i = 20000*0.065*1
i = 1300
So Mark earns $1,300 in simple interest each year.
Given:
The given equation is

To find:
All the real solutions.
Solution:
We have,

It can be written as


Using zero product property, we get
and 
and 
and 
We know that
is an imaginary number because there is a negative sign under the square root.
Therefore,
is the only real solution of the given equation.
The two parabolas intersect for

and so the base of each solid is the set

The side length of each cross section that coincides with B is equal to the vertical distance between the two parabolas,
. But since -2 ≤ x ≤ 2, this reduces to
.
a. Square cross sections will contribute a volume of

where ∆x is the thickness of the section. Then the volume would be

where we take advantage of symmetry in the first line.
b. For a semicircle, the side length we found earlier corresponds to diameter. Each semicircular cross section will contribute a volume of

We end up with the same integral as before except for the leading constant:

Using the result of part (a), the volume is

c. An equilateral triangle with side length s has area √3/4 s², hence the volume of a given section is

and using the result of part (a) again, the volume is

Answer:
5.714 liters of the 5% solution and 4.286 of the 40%.
Step-by-step explanation:
Let x be the volume of 40% solution and y = volume of the 5% solution.
x + y = 10
0.40x + 0.05y = 0.20(x + y)
From the first equation x = 10 -y so we have:
0.40(10 - y) + 0.05y = 0.20( 10 - y + y)
4 - 0.40y + 0.05y = 2
-0.35y = -2
y = 5.714 liters of the 5%.
and x = 10 - 5.714 = 4.286 liters of the 40% solution.
Step-by-step explanation: