A parent has washed some nappies in a strong bleach solution and wishes to rinse them so that they contain as weak a bleach solution as possible. By wringing out, the nappies can be made to contain just half a litre of solution. Show that two thorough rinses, such that the solution strength is uniform, the first using 12 litres of water and the second using 8 litres of water, reduces the strength of the
1 425
If 20 litres of clean water is all that is available and the parent is prepared to do only two rinses, how best should the water be divided between the two rinses?

Answers

Answer 1

Answer:

a) Two thorough rinses gives;

1/25 × 1/2 × 2/17 strong bleach/L = 1/425 strong bleach/L

b) The water should be divided into two quantities of 10 liters each

Step-by-step explanation:

The given parameters are;

The initial volume of strong bleach solution in the nappies = 1/2 Liters

The volume of water first used to rinse = 12 liters

The volume of water used in the second rinse = 8 liters

Therefore, we have;

The total volume of the water and the concentrated bleach in the first rinse = 1/2 + 12 = 12.5 Liters

The new concentration of the bleach in the first rinse water = (1/2 strong bleach)/12.5 L = (1/2 strong bleach)/25/2 L = 1/2×2/25 = 1/25 strong bleach/L

The volume of the first rinse introduced in the second rinse = 1/2 Liters

The concentration of the bleach introduced in the second rinse = The new concentration of the bleach in the first rinse water = 1/25 strong bleach/L

The volume of water added in the second rinse = 8 liters

The total volume of the water and the bleach in the second rinse = (8 + 1/2) liters = 8.5 liters

The concentration of bleach in the second rinse = (The concentration of the bleach introduced in the second rinse × (Volume of bleach solution introduced in the second rinse))/(The total volume of the water and the bleach in the second rinse)

The concentration of bleach in the second rinse = (1/25 strong bleach/L × 1/2 L)/(8.5 Liters)

The concentration of bleach in the second rinse = (1/25 strong bleach/L × 1/2 L)/(17/2 Liters) = 1/25 × 1/2 × 2/17 strong bleach/L = 1/425 strong bleach/L

b) The the quantity of water in the first rinse = x

The amount of water in the second rinse = 20 - x

The concentration of bleach in the first rinse = 1/2/(x + 1/2) = 1/(2·x + 1)

The concentration introduced in the second rinse = 1/2 × 1/(2·x + 1) = 1/(4·x + 2)

The total volume of water and bleach introduced in the second rinse = (20 - x + 1/2) = 20.5 - x

The concentration of bleach in the second rinse = 1/(4·x + 2)/(20.5 - x)

The minimum value for the concentration can be found from taking the derivative of the function for the concentration and equation to zero as follows;

[tex]\dfrac{\mathrm{d} \dfrac{1}{\left ( 4\cdot x + 2 \right )\cdot \left ( 20.5 - x \right )}}{\mathrm{d} x} = \dfrac{2\cdot \left ( x - 10 \right )}{\left ( 2\cdot x + 1 \right )^{2}\cdot \left ( 20.5 - x \right )^{2}} = 0[/tex]

2·(x - 10) = 0

x = 0/2 + 10 = 10

x = 10

The the quantity of water in the first rinse = x = 10 liters

The the quantity of water in the first rinse = 10 liters

The amount of water in the second rinse = 20 - x = 20 - x = 20 - 10 = 10 liters

The amount of water in the second rinse = 10 liters

The water should be divided into two quantities of 10 liters each

Therefore, the water should be divided into two quantities of 10 liters each to give a final bleach solution concentration of 1/(4·x + 2)/(20.5 - x) = 1/(4×10 + 2)/(20.5 - 10) = 1/42 × 1/10.5 = 1/441 concentration/liter.

Answer 2

Answer: a) Two thorough rinses gives;

1/25 × 1/2 × 2/17 strong bleach/L = 1/425 strong bleach/L

b) The water should be divided into two quantities of 10 liters each


Related Questions

There are 28 roses and 35 carnations. Anna is making flower arrangements using both flowers, what is the maximum number of arrangements she could make?

Answers

Answer:

The maximum amount of flower arrangements she can make are 28.

Step-by-step explanation:

There are enough roses and carnations to make 28 flower arrangements. There will still be leftover carnations but that's fine.

You do this by finding the smaller number of flowers and grouping them with the other flower so it makes a group of two. If the other flower had 2x the amount of the smaller flower, them group them in a group of 3;  1 : 2

But this is only used to make the maximum amount. this is not the efficient way to go but this is the way to go if you are finding the max amount.

PLS ANSWER THIS CORRECTLY AND GET 30 PTS AND BRAINLY

Answers

3.988906 cause look at it

Answer:

(-0,1)        

Really sorry if it's wrong! Have a good day!!

2.5 as a simplified fraction​

Answers

Answer:

I believe it would be 5/2

Select the equation that most accurately depicts the word problem.

Mary Lou has 2 more nickels than pennies, and she has 30 coins all together. Use x for the number of pennies.

a. x + 2 = 30
b. x + (x + 2) = 30
c. 2(x + 2) = 30
d. 2x + 30 = 5

Answers

Answer:

B. x + (x+2) = 30

Step-by-step explanation:

If x equals pennies, then one part of the statement should include an addition of 2, along with the additions of the value of pennies; and it should all equal 30.

Answer:

B. x + (x + 2) = 30

Step-by-step explanation:

x = number of pennies

y = number of nickels

x + y = 30

y = 30 - x

She has two more nickels then pennies, therefore:

y = x + 2

30 - x = x  + 2

30 = x + x + 2

x + (x + 2) = 30

multiplying a number by (−1) results in its (blank)

Answers

The answer is it’s inverse.

Multiplying a number by -1 changes the sign of the number, which is the inverse of the original number.

Answer:

Makes it negative

Step-by-step explanation:

example:5 multiplied by (-1) = -5

In the accompanying diagram of parallelogram abode m\angle A=(2x+10) and m/angle=3x. Find the number of degrees in m/angle B (open pictures for diagram)

Answers

Answer:

x = 55

Explanation:

In a parallelogram, the sum of each two consecutive angles is 180°.

In the given parallelogram ABCD, we can note that angles A and B are consecutive angles. This means that their summation is 180°

Therefore:

∠A + ∠B = 180

2x + 15 + x = 180

3x + 15 = 180

3x = 180 - 15

3x = 165

x = 165 / 3

x = 55

Now we can check:

angle A = 2(55) + 15 = 125°

angle B = 55°

angle A + angle B = 125 + 55 = 180°

Hope this helps :)

Solve for Y
-2х + 4y = 16
а. y = 2х + 4
b. у = -2х + 4
с. y = 1/2 х + 4
d. y = 1/2 x - 4

Answers

the answer is c. y= 1/2x+4

5 apples weight 0.6 kilograms. All of our apples weigh the same. How many kilograms will 12 apples weigh?

Answers

Answer:

I think 7.2

Step-by-step explanation:

I multiply .6 to 12 and got that

.................................................................................................................................................................................................................................................................................................................................................................................................

Answers

Answer:

47.022

Step-by-step explanation:

Answer: 47.022

Step-by-step explanation:

Pic

Find the tip amount of a $30 bill with a 20% tip

Answers

Answer:

$6

Step-by-step explanation:

Ok, first thing is first, we need to find what 20% of 30 is. We do that by setting 20% in decimal form and multiplying that by 30.

So first,

0.20 * 30

We cross out the zero in 30 and move the decimal point one spot to the right in 0.20. So now we have:

= 2.0 * 3

Which really is,

= 2 * 3

Which equals,

6

Or,

$6

Yes! We got our answer! Nice work!

(The total bill including the tip would be $36 in case you needed to know)

Can you please help me? I will give brainliest, I appreciate it :) Thanks!

Answers

Answer:

I going to say this should be easy because there must be a f(x) in a function so I think the answer is A.

Step-by-step explanation:

I think that functions must have f(x) in the equation.

Which statement describes the behavior of the graph of the function shown at the vertical asymptotes?

As x approaches -7 from the left, y approaches ∞.
As x approaches -7 from the right, y approaches -∞.
As x approaches 7 from the left, y approaches –∞.
As x approaches 7 from the right, y approaches –∞.

Answers

Answer:

its D

Step-by-step explanation:

if you look at the graph I shared, the end behaviors are

As x approaches -7 from the left, y approaches -∞.

As x approaches -7 from the right, y approaches ∞.

As x approaches 7 from the left, y approaches ∞.

As x approaches 7 from the right, y approaches –∞.

The only one that maches this description is D

Answer:d

Step-by-step explanation:

just d

What is 13 / 143 as a unit fraction

Answers

Answer:1/11

Just got it using some brain cells >:)

Answer:

1/11

Step-by-step explanation:

13/143=1/11

I need help with 43. . . .

Answers

Answer:

B

Step-by-step explanation:

You have 3 red marbles and say x non-red marbles. Then you get the following equation:

[tex]\frac{3}{3+x} = \frac{1}{5}[/tex]

We can solve this equation by doing cross multiplication:

[tex]3*5 = 3 + x[/tex]

And solve for x to be 12.

Triangle X Y Z is shown. The length of side X Y is (9 n + 12) feet and the length of side X Z is (15 n minus 6) feet. Angles X Y Z and Y Z X are congruent. Consider isosceles ΔXYZ. What is the value of n? What is the measure of leg XY? ft What is the measure of leg XZ? ft

Answers

*the figure is shown in the attachment

Answer/Step-by-step explanation:

Since <XYZ and <YZX are said to be congruent, therefore, the side opposite to each of the angle are also equal. Therefore, ∆XYZ is an isosceles ∆.

Find the value of n by creating an equation to solve for n:

XY = (9n + 12) ft

XZ = (15n - 6) ft

XY = XZ (2 equal lengths of isosceles ∆)

9n + 12 = 15n - 6 (substitution)

Combine like terms

9n - 15n = - 12 - 6

-6n = -18

Divide both sides by -6

-6n/-6 = -18/-6

n = 3

Find the length of leg XY by substituting n = 3 into XY = (9n + 12) ft.

XY = (9(3) + 12) ft

XY = (27 + 12) ft

XY = 39 ft

Find the length of leg XZ by substituting n = 3 into XZ = (15n - 6) ft.

XZ = (15(3) - 6) ft

XZ = (45 - 6) ft

XZ = 39 ft

Answer:

1st box: 3

2nd box: 39

3rd box: 39

Have a great day, remember to wear a mask! :)

3 to the 7th power time 3 to the -4th

Answers

Answer:

3 to the 3rd power

Step-by-step explanation:

Jonathan forgot his math homework on the kitchen table and left for school without it. He biked at the speed of 15 mph. His mother saw the homework when he was already 1 mile from home, and started chasing him. She drove at a speed of 25 mph and caught him at the school entrance. How far is the school from Jonathan's home?

Answers

Answer:

2.5 miles

Step-by-step explanation:

Let the distance be x

Then Jonathan biked for

x/15 hours

His mother drew for

x/25 hours

The time difference is

1/15 hours

So we have

x/15 - 1/15 = x/25(x - 1)/15 = x/2515x = 25x - 2525x - 15x = 2510x = 25x = 25/10x = 2.5 miles

1) If the mean is 15.5 and the standard deviation is 2.5, Label b, c, d, e, and f​

Answers

Answer:

I accidentally clicked I can’t click out

Step-by-step explanation:

Sorry

Objects that are in the same plane are called _______________ . *

Answers

Answer:

black lines....I think

Each baseball hat costs the same amount of money. The cost for 18 baseball hats was $216. What is the unit price?

Answers

Answer:

15%

Step-by-step explanation:

if u did the 216 divided by the 18 then that's how u get estimated number

7. Evaluate the following expression for n = 4.
2n? - 8

Answers

0
The reason is 2 times 4 equals 8 and 8-8 is 0

Simply replace n with 4 and do the math.

2n - 8

Let n = 4

2(4) - 8

8 - 8 = 0

Answer: 0

ASAP ASAP ASAP
PLEASE HELP ME

Answers

Answer:

d

Step-by-step explanation:

Answer:

I rlly don't know how to help you bruh

Step-by-step explanation:

Why I can't understand the question and as to what they mean by if you fold it as shown though i know they probably mean where the shapes on the side are I say find someone else or take a wild guess.

Bus A and Bus B leave the bus depot at 3 pm.
Bus A takes 25 minutes to complete its route once and bus B takes 30 minutes to complete its route once.
If both buses continue to repeat their route, at what time will they be back at the bus depot together?
Assume the buses have no breaks in between routes.
Give your answer as a 12-hour clock time.

Answers

im assuming that the buss only repeat the rout once? so in total they do 2 routes?

bus a at 3:50 and bus b at 4:00

I really need help! I don't understand..

Thanks!​

Answers

8.30*14.50
Answer
123.25

40 POINTS FOR AWNSER

Sal's Sandwich Shop sells wraps and sandwiches as part of its lunch specials. The profit on every sandwich is $2, and the profit on every wrap is $3. Sal made a profit of $1,470 from lunch specials last month. The equation 2x + 3y = 1,470 represents Sal's profits last month, where x is the number of sandwich lunch specials sold and y is the number of wrap lunch specials sold.

Change the equation to slope-intercept form. Identify the slope and y-intercept of the equation.


Describe how you would graph this line using the slope-intercept method. Be sure to write using complete sentences.


Write the equation in function notation. Explain what the graph of the function represents. Be sure to use complete sentences.


Graph the function. On the graph, make sure to label the intercepts. You may graph your equation by hand on a piece of paper and scan your work or you may use graphing technology.


Suppose Sal's total profit on lunch specials for the next month is $1,593. The profit amounts are the same: $2 for each sandwich and $3 for each wrap. In a paragraph of at least three complete sentences, explain how the graphs of the functions for the two months are similar and how they are different.

Answers

The answer is 247=x-73y

An empty erlenmeyer flask that weighs 245.8 g is filled with 125 mL of carbon tetrachloride . The weight of the flask and carbon tetrachloride is found to be 444.6 g. From this information , calculate the density of carbon tetrachloride .​

Answers

Answer:

The density is 1.59 g/mL. Therefore, the substance will NOT float in water.

Step-by-step explanation:

The following data were obtained from the question:

Mass of empty flask = 245.8 g

Mass of flask + CCl₄ = 444.6 g

Volume of CCl₄ = 125 mL

Density of CCl₄ =?

Next, we shall determine the mass of carbon tetrachloride, CCl₄. This can be obtained as follow:

Mass of empty flask = 245.8 g

Mass of flask + CCl₄ = 444.6 g

Mass of CCl₄ =.?

Mass of CCl₄ = (Mass of flask + CCl₄) – (Mass of empty flask)

Mass of CCl₄ = 444.6 – 245.8

Mass of CCl₄ = 198.8 g

Finally, we shall determine the density of carbon tetrachloride, CCl₄ as follow:

Mass of CCl₄ = 198.8 g

Volume of CCl₄ = 125 mL

Density of CCl₄ =?

Density = mass / volume

Density of CCl₄ = 198.8 / 125

Density of CCl₄ = 1.59 g/mL

The density of water is 1 g/mL. Since the density of carbon tetrachloride, CCl₄ (i.e 1.59 g/mL) is bigger than that of water, the substance will not float in water.

The density of carbon tetrachloride is 1.59 grams per milliliter.

Given that an empty erlenmeyer flask that weighs 245.8 g is filled with 125 mL of carbon tetrachloride, and the weight of the flask and carbon tetrachloride is found to be 444.6 g, to determine the density of carbon tetrachloride the following calculation must be performed:

Subtract the weight of the empty flask from the weight of the full flask, and then divide this result by 125 (the milliliters of carbon tetrachloride).

(444.6 - 245.8) / 125 = X 198.8 / 125 = X 1.59 = X

Therefore, the density of carbon tetrachloride is 1.59 grams per milliliter.

Learn more in https://brainly.com/question/952755


¡¡. PLEASE HELP !!!!

Answers

The answer to question 3 is 4

Given m|n, find the value of x.
t
m
(9x+23)
(10x+6)°
Someone help?

Answers

Since M is parallel to N that means they would have to equal each other.

Given f(x) = -x + 3, solve for x when f(x) = 4.

Answers

Answer:

x=-1

Step-by-step explanation:

f(x)=f(x)

-x+3=4

angle 1 and angle 2 are supplementary. m angle1 = 3x - 4 and m angle2 = 8x - 14. Find the measure of each angle.

Answers

Answer:

50° and 130°

Step-by-step explanation:

Angle1 and angle2 are supplementary. So, sum of angle1 and angle2 is 180°

3x-4+8x-14=180°

11x-18=180°

11x=198°

x=18°

Angle1 = 3*18 -4 = 50°

Angle2 = 8*18 -14= 130°

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