Foactoring Diff/ Sum of Cubes Factor completely

Suppose that a large mixing tank initially holds 500 gallons of water in which 50 pounds of salt have been dissolved. Another br

Lina20 [59]

Answer:

The differential equation for the amount of salt A(t) in the tank at a time t > 0 is $\frac{dA}{dt}=12 - \frac{2A(t)}{500+t}$ .

Step-by-step explanation:

We are given that a large mixing tank initially holds 500 gallons of water in which 50 pounds of salt have been dissolved. Another brine solution is pumped into the tank at a rate of 3 gal/min, and when the solution is well stirred, it is then pumped out at a slower rate of 2 gal/min.

The concentration of the solution entering is 4 lb/gal.

Firstly, as we know that the rate of change in the amount of salt with respect to time is given by;

$\frac{dA}{dt}= \text{R}_i_n - \text{R}_o_u_t$

where, $\text{R}_i_n$ = concentration of salt in the inflow $\times$ input rate of brine solution

and $\text{R}_o_u_t$ = concentration of salt in the outflow $\times$ outflow rate of brine solution

So, $\text{R}_i_n$ = 4 lb/gal $\times$ 3 gal/min = 12 lb/gal

Now, the rate of accumulation = Rate of input of solution - Rate of output of solution

= 3 gal/min - 2 gal/min

= 1 gal/min.

It is stated that a large mixing tank initially holds 500 gallons of water, so after t minutes it will hold (500 + t) gallons in the tank.

So, $\text{R}_o_u_t$ = concentration of salt in the outflow $\times$ outflow rate of brine solution

= $\frac{A(t)}{500+t} \text{ lb/gal } \times 2 \text{ gal/min}$ = $\frac{2A(t)}{500+t} \text{ lb/min }$

Now, the differential equation for the amount of salt A(t) in the tank at a time t > 0 is given by;

= $\frac{dA}{dt}=12\text{ lb/min } - \frac{2A(t)}{500+t} \text{ lb/min }$

or $\frac{dA}{dt}=12 - \frac{2A(t)}{500+t}$ .

4 0

3 years ago

The image shows three tennis balls enclosed in a cylindrical can. Choose all that are correct. The volume of a single tennis bal

Fynjy0 [20]

Answer:

The volume of a single tennis ball is $14.14\ in^{3}$

The volume of three tennis balls is $42.42\ in^{3}$

Step-by-step explanation:

Step 1

Find the volume of a single tennis ball

we know that

The volume of a sphere is equal to

$V=\frac{4}{3}\pi r^{3}$

where r is the radius of the sphere

In this problem

$r=3/2=1.5\ in$

substitute

$V=\frac{4}{3}\pi (1.5)^{3}$

$V=14.14\ in^{3}$

Step 2

Find the volume of the can

we know that

the volume of the cylinder is equal to

$V=\pi r^{2} h$

where r is the radius of the cylinder

h is the height of the cylinder

in this problem we have

$r=3/2=1.5\ in$

$h=8.4\ in$

substitute

$V=\pi (1.5)^{2}(8.4)$

$V=59.38\ in^{3}$

Statement

case A) The volume of a single tennis ball is $14.14\ in^{3}$

The statement is true

See the procedure in Step 1

case B) The volume of the can is $56.55\ in^{3}$

The statement is false

The volume of the can is $59.38\ in^{3}$ --> see the procedure Step 2

case C) The empty space inside the can is $14.13\ in^{3}$

The statement is false

To find the empty space subtract the volume of three tennis ball from the volume of the can

$59.38\ in^{3}-3*14.14\ in^{3}=16.96\ in^{3}$

case D) The volume of three tennis balls is $42.42\ in^{3}$

The statement is true

To find the volume of three tennis balls multiply the volume of a single tennis ball by three

$14.14*3=42.42\ in^{3}$

8 0

3 years ago

What is the surface area of the figure?

likoan [24]

We can split it up into a net
actually, here is a hack

notice that indented side?
we can take the plane and push it so it makes 4 sides, neat

ok, so we now just have 4 normal sides and 2 L shapes

L shape can be cut into 2 rectangles
5 by 5 and 5 by 10 so total of 75 is the L
2 L's so
2*75=150

the sides
4 of them
they all are 10 by 3
10*3*4=120

toatl is 150+120=270

answer is A

3 0

3 years ago

Read 2 more answers

a washer and a dryer cost 1020$ combined, the washer costs 70$ more than the dryer. What is the cost of the dryer?

finlep [7]

Answer:

$950

Step-by-step explanation:

x+70=1020 so subtract 70 from both sides

x=950 cost of dryer

1020-950=70 washer is 70 more than dryer

6 0

3 years ago

Jack and Jillian sell apples at a produce stand. Jillian earns $2 for each bag of apples she sells. At the end of the week, Jack

elena-14-01-66 [18.8K]

We are given that Jack and Jillian sell apples at a produce stand .

We are given that an expression which shows Jack's earning=2x-8

We have to find that first term what represent in the given expression

Jillian earns for each bag of apples she sells=$2

Let Jillian sold number of bags of apples =x

Then ,Jillian earn total at the end of the week =

Jack has earned $ 8 less than Jillian earn

Therefore, total earning of jack=

In the given expression the first term 2x represent the earning of Jillian.

5 0

3 years ago

Foactoring Diff/ Sum of Cubes Factor completely​

Foactoring Diff/ Sum of Cubes Factor completely