# Posts by mark

Total # Posts: 1,608

**Biochem**

What is the maximum amount of ethanol (in millimoles) that could theoretically be produced under the following conditions? Condition: A cell-free yeast extract is placed in a solution that contains 3.50 × 102 mmol glucose, 0.30 mmol ADP, 0.30 mmol Pi, 0.60 mmol ATP, 0....

*April 3, 2013*

**Math (Percentage)**

In a class of 40 , 12 students failed the exam. What was the passing rate of the said class?

*April 3, 2013*

**Math (Percentage)**

In a class of 40 , 12 students failed the exam. What was the passing rate of the said class?

*April 3, 2013*

**Math (Algebra)**

A jar contains x nickels and y quarters only. What percentage of the total number of coins are quarters?

*April 3, 2013*

**Math**

A newly designed international airport is planning to label its gates. Each gate must be assigned a letter from the alphabet from A to M (13 in all), and a number from 1 to 15. To avoid confusion, any two gates must be assigned a different letter, or a different number (or ...

*April 3, 2013*

**Math**

A newly designed international airport is planning to label its gates. Each gate must be assigned a letter from the alphabet from A to M (13 in all), and a number from 1 to 15. To avoid confusion, any two gates must be assigned a different letter, or a different number (or ...

*April 2, 2013*

**physics**

A bridge is supported at both ends (500m between supports). A Car (250 Kg) is at 100m from the left support. A truck (4000 Kg) is at 200m from the left support. Find the forces on the supports

*March 28, 2013*

**Science help**

D. All of the above

*March 25, 2013*

**math problem**

A piece of wire 24 cm long is cut into two pieces and each piece is bent to form a square . Find the lenght of each piece of wire in order to maximize the sum of the area of the two squares?

*March 21, 2013*

**chem**

This question has already been posted. Please don't flood the site with repetitive posts. The tutors work very hard to answer as many as they can.

*March 14, 2013*

**Chemistry**

Thank you Mr. Devron! I learnt something from you as well. The compound is Antimony Pentoxide, and I did indeed not realize that after dividing by the lowest moles you can multiply!

*March 14, 2013*

**Chemistry**

You need to know the molar ratio for Antimony Oxide! Since Sb has an oxidation of +3 and Oxygen has a oxidation of -2, you need two Sb atoms and three O atoms. Sb2O3 Figure out how many moles you have of antimony and oxygen.. 51.5 g Sb * 1 mol/ 121.76 g= 0.43 moles Sb 16.9 g O...

*March 14, 2013*

**Is this correct?**

Thank you.

*March 14, 2013*

**Is this correct?-Mean value Theorem**

Sorry I forgot to include the topic.

*March 14, 2013*

**Is this correct?**

What values (c) if any are predicted by the mean value theorem for the function f(x)= (x-2)^3 on the interval [0,2]? I got x= 4 and x=0, since x=0 is within the interval I chose that as my answer. Thank you.

*March 14, 2013*

**Chemistry**

You will have to find the molar mass here.. 200 ml * 0.1 mol/ L * 1 L/ 1000 mL= 0.02M 250 ml* 0.2M/ L * 1L/ 1000 mL= 0.05M N I somehow feel this problem is incomplete or either I am unable to understand the chemical compound name. Is there anymore to it?

*March 14, 2013*

**Slope- Derivative**

Thank you!

*March 14, 2013*

**Slope- Derivative**

Find the slope of f(t)= sqrt((1-sin (2t)) a) at point (0,1) i got -1 b) at origin i got 1 is this right thanks

*March 14, 2013*

**Derivative-Word Problem**

I read more about related rates, and have now understood these types of problems. Thank you!

*March 14, 2013*

**Derivative-Word Problem**

Volume in liters of antifreeze remaining in a leaking radiator after t minutes is V= 20- 2t- 0.1t^2 a) how long does it take to drain the antifreeze mixture from the radiator? i got t= 10 b) how fast is volume changing when t=5? i got 9.75 is this right. thanks

*March 14, 2013*

**Word Problem-Calculus**

My fault lied in plugging in directly. Thank you for showing me the steps.

*March 14, 2013*

**Word Problem-Calculus-Already Solved-Please check?**

Thank you!

*March 14, 2013*

**Word Problem-Calculus**

A spherical balloon is being inflated in such a way that its radius increases at a rate of 3 cm/min. If the volume of the balloon is 0 at time 0, at what rate is the volume increasing after 5 minutes? my answer is 45 cm/min. is this right. thanks

*March 14, 2013*

**Cos-Derivative**

Thanks!

*March 14, 2013*

**Cos-Derivative**

y= (cos^3 x) (cos 3x) I got -3 sin(3x) cos^3x - 3 sin(x) cos (3x) cos^2 (x) using the product rule Is this right? Thanks.

*March 14, 2013*

**Derivatives**

I have taken that into consideration; thank you!

*March 14, 2013*

**Derivatives**

I got 12 sin (3x-1)^2 cos (3x-1)^2 * (3x-1) as my final answer. Is this in the correct simplified form ?

*March 14, 2013*

**Derivatives**

I'm not sure if this is correct. Can someone clarify thanks.

*March 14, 2013*

**Derivatives**

what is derivative of sin^2 (3x-1)^2 ? dy/dx (sin^2 (x))= 2 sin x cos x dy/dx (3x-1)^2= 6(3x-1) chain rule? = 2 sin ((3x-1)^2) cos ((3x-1)^2) * 6(3x-1) Please help. Thank you

*March 14, 2013*

**Math: Please check**

This is correct!

*March 14, 2013*

**Math: Please check**

W= 5L So the side lengths are 5L and L. by definition of a right triangle (5L)^2 + (L)^2= ? 25L^2 + L^2= 26L^2 This matches choice C.

*March 14, 2013*

**math problem**

- Mr. Hermann, a stamp collector , sold 2 stamps for $5000 each. Based on his cost , he made a 25% profit on one stamp and lost 20% on the other stamp. What was Mr. Hermann's total loss on the two transactions? - There are five chidren in the Roberts family. Amy and Ariel ...

*March 13, 2013*

**Pleass Help With MATH**

Read this story to answer the following questions: Diego is building an architectural rendering of a house. For a portion of the roof, Diego cuts and folds a net for a triangular prism. the base of the prism is an isoceles triangle. the triangle has a base of 24 inches and a ...

*March 6, 2013*

**3rd math**

2 53 x7 371 No rick is not correct because 53x7=371

*March 6, 2013*

**mAth**

story: Diego is building an architectural rendering of a house. For a portion of the roof, Diego cuts and folds a net for a triangular prism. the base of the prism is an isoceles triangle. the triangle has a base of 24 inches and a height of 5 inches. the distance between the ...

*March 6, 2013*

**Statistics**

The rate of chlamydia infection was reported as 2.78% in a recent year. Under certain conditions, a preliminary screening test for the chlamydia bacterium is correct 96% of the time. One person is randomly selected from the population. find the true positive. Can someone ...

*March 6, 2013*

**stats**

okay, so I think the true positive is 96%, but what about the true negative, false positive and the false negative?

*March 6, 2013*

**stats**

The rate of chlamydia infection was reported as 2.78% in a recent year. Under certain conditions, a preliminary screening test for the chlamydia bacterium is correct 96% of the time. One person is randomly selected from the population. find the true positive. Can someone ...

*March 6, 2013*

**Math**

He spent 2/3 of his money. The movie cost 6. How much does he have left

*March 5, 2013*

**physics**

A softball bat is rotating at 460 rotations per minute at contact with the ball. What is the angular velocity in radians?

*February 25, 2013*

**physics**

A skater rotates 760 degrees clockwise, stops, and rotates counterclockwise for 340 degrees. What is her angular distance? Angular displacement?

*February 25, 2013*

**physics**

A softball player swings her bat through her full range of motion of 392 degrees in 0.3 secs. What is the angular velocity of the bat? What is the average acceleration of the bat?

*February 25, 2013*

**physics**

In order for a ski jumper to attain maximum projectile distance she must reach a velocity of 30m/s. of the runway of the takeoff ramp is 70m long, how quickly ust she accelerate?

*February 25, 2013*

**physics**

A freestyle skier hits the take off ramp with an initial velocity of 17.5 m/s with a purely vertical take off (90 degrees). What is the peak height that the skier will reach?

*February 25, 2013*

**physics**

A shot-‐putter releases the 16 lbs. shot at an angle of 41 degrees. If the shot travels a horizontal distance f 34 m to reach its peak at midflight, how high did the shot go and what is the displacement of the resulting vector at midflight?

*February 25, 2013*

**physics**

A cyclist has a final velocity of 30 m/s after coasting down hill for 2 seconds. If the cyclist underwent a constant acceleration of 7.5m/s2 during the descent, what was his initial velocity at the top of the hill?

*February 25, 2013*

**geography**

what is exsolation?

*February 24, 2013*

**Physics**

A pond is 12 metres across. The crests of two successive waves are 60.0 cm apart and they each move across the pond in 15 seconds. a)What is the velocity of the waves? b)What is the frequency of the waves? c)What is the period of the waves?

*February 24, 2013*

**Math**

The sides of the triangle at right are formed by the graphs of 3x+ 2y = 1, y = x − 2, and −4x+ 9y = 22. Is the triangle isosceles? How do you know?

*February 12, 2013*

**Math**

75/15 = 5. So each baseball weighs 5 ounces. 15/5 = 3. Three baseballs weigh 15 ounces.

*February 11, 2013*

**Math**

Josh borrows some money on which he makes monthly payments of $125.43 for 3 years. If the interest rate is 5.4%/a compounded monthly, what will be the total amount of all of the payments at the end of the 3 years?

*February 11, 2013*

**Math**

Maria bought 5 cans of tennis balls. Each can contained 3 tennis balls. How many tennis balls did Maria buy altogether?

*February 11, 2013*

**Algebra**

There are 4 children and 17 adults.

*February 10, 2013*

**Math**

Explain It Why is 10-0=10, but 0/10=0? Explain

*February 10, 2013*

**chem**

The ΔHvap of a certain compound is 34.68 kJ·mol–1 and its ΔSvap is 93.60 J·mol–1·K–1. What it the boiling point of this compound?

*February 10, 2013*

**math**

taylor was having a party.she invited 20 friends to her party, if each person shook hands with every other person .how many handshakes would there be? please explain,thanks

*February 10, 2013*

**chemistry**

OK thanks.... In the question, and in the example in the textbook there was no example of using an ICE table. Tables make assigning values so much easier

*February 10, 2013*

**chemistry**

Sorry I should have left that out, it's just the formula HCOOH(aq) <-----> H^+ (aq)+ HCOO^-(aq)

*February 10, 2013*

**chemistry**

HCOOH(aq) <-----> H^+ (aq)+ HCOO^-(aq) The equilibrium constant (Ka) for Reaction 3 at 25 °C is 1.80 × 10−4 mol dm−3. Calculate the equilibrium concentration of hydrogen ions if the concentration of formic acid at equilibrium is 0.00500 mol dm−3

*February 10, 2013*

**science**

Oh yeah! Those values apply to this equation: HCOOH(aq) <-----> H^+ (aq)+ HCOO^-(aq)

*February 10, 2013*

**science**

The equilibrium constant (Ka) for Reaction 3 at 25 °C is 1.80 × 10−4 mol dm−3. Calculate the equilibrium concentration of hydrogen ions if the concentration of formic acid at equilibrium is 0.00500 mol dm−3. (Show all of your working and give your ...

*February 10, 2013*

**Math grade 8 (algebra)**

The perimeter of the square is 2cm longer than the perimeter of the triangle.Write an equation for the perimeter of the square and then determine the length of each side of the square. Thank you in advance.

*February 7, 2013*

**Math**

Red beads = 16 Yellow beads = 16-8 = 8 Green beads = 16 +7 = 23 16 red, 8 yellow, 23 green is 16+8+23 = 47 total beads

*February 5, 2013*

**English**

choosing a conjunction and the relationship it expresses: ------you buy a rare manuscript, make certain of its authenticity. I used "Before" but it would be "time" or Should I use "If" and it would be "condition" This is so confusing!!!

*January 29, 2013*

**Chemistry**

I'm asked to tell which of the following peptide segments is most likely to be part of a stable Alpha Helix at physiological pH? Only 1 can be chosen 1. gly-gly-gly-ala-gly 2. gly-arg-lys-his-gly 3. pro-leu-thr-pro-trp 4. lys-lys-ala-arg-ser 5. glu-leu-ala-lys-phe 6. glu-...

*January 27, 2013*

**Chemistry**

You have 475 mL of an 0.47 M acetic acid solution. What volume (V) of 1.10 M NaOH solution must you add in order to prepare an acetate buffer of pH = 5.00?

*January 19, 2013*

**finance**

1. The U.S. ﬁnancial system is composed of: (1) policy makers, (2) a monetary system, (3) ﬁnancial institutions, and (4) ﬁnancial markets. Indicate which of these components is associated with each of the following roles: a. accumulate and lend/invest ...

*January 19, 2013*

**finance**

ATM Banc has the following liabilities and equity categories: Deposits $9 million, Other liabilities $4 million, Owners’ capital $2 million. . a. What would be the bank’s total liabilities and capital if owners’ capital were half the size of other liabilities? b...

*January 19, 2013*

**arithmetic**

change 12/23 into a decimal to the nearest hundreth's

*January 16, 2013*

**statistics**

did you get an answer?

*January 15, 2013*

**statistics**

these numbers are wrong. did you change the numbers??? where are you getting this data???

*January 14, 2013*

**math**

which digits are in the ones place of a number multiplied by 5? a.0 or 1 b.0 or 5 c.2 or 4 d.2 or 5 Is it b????

*January 14, 2013*

**math**

which digits are in the ones place of a number multiplied by 5? a.0 or 1 b.0 or 5 c.2 or 4 d.2 or 5 Is it b????

*January 14, 2013*

**help please**

was this correct??

*January 10, 2013*

**help please**

many children have more than one figure towards whom they direct attachment behavior. These figures are not treated alike but there is a strong bias for a child to direct attachment behavior mainly towards one particular person. Bowlby used the term "monotropy" to ...

*January 10, 2013*

**help please**

what does reseach show about the child;s relationship with the primary parental figure when the child has additional attachments to other people?

*January 10, 2013*

**English-Native speakers**

Thank you ;)

*January 8, 2013*

**English-Native speakers**

Can someone please make this sentence more "English"? THE ROLE OF ILLUSTRATIONS IN CHILDREN'S BOOKS WRITTEN BY GERMAN WRITERS AND RELEASED AFTER 1950. This is supposed to be the title

*January 8, 2013*

**Ms. Sue (History)**

Thanks

*December 20, 2012*

**Ms. Sue (History)**

The Europeans raised their own tariff which caused a trade protection war. The American merchants had enormous surpluses and no market to sell their goods. This would cause a fall in prices and industrial instability. Am I on the right track?

*December 20, 2012*

**History**

Why was the Fordney-McCumber Tariff of 1922 a BAD thing for the U.S. Economy? There seems to so many and I would like to know the most important ones.

*December 20, 2012*

**math**

draw the shape of an ice-cream cone wrapper when it is slit from the edge to the center point and flattened out

*December 14, 2012*

**Math**

Find the positive number such that 1/2 of the number multiplied by 1/3 of the number, multiplied by 1/6 of the number is equal to the number itself.

*December 12, 2012*

**English**

I need to correct the verb in this sentence. If we would have had the engine tuned, I'm sure we would not be stranded on the highway now. Is this correct? If we had had the engine tuned, I'm sure we would not be stranded on the highway now.

*December 11, 2012*

**Algebra**

Can you explain how you got those answers, Raj? Thank You!

*December 5, 2012*

**Algebra**

-Alfonso can write 100 practice problems for the math team in 20 hours, Beauregard can write the same number of problems in 30 hours, and Clyde can write the number of problems in 40 hours. Working together, at what time will the three of them finish writing 100 practice ...

*December 5, 2012*

**Chemistry**

7.40 g of liquid methanol, CH3OH, are placed in an empty 20.0 L container at 45.0°C. What will be the pressure in the container when equilibrium is established? Assume the temperature remains constant and the volume of any liquid is negligible. The vapor pressure of ...

*December 4, 2012*

**math**

how many gallons would a hole 100ft deep by 6ft wide hold

*December 3, 2012*

**English**

Thank you very much, Ms. Sue

*November 28, 2012*

**English**

"Understanding the cause for Bartleby's reason to be an introvert and to offer polite refusals when asked to do something would suggest he deserves either sympathy or disdain." I need to reword the whole thesis using different words but meaning the same thing. I ...

*November 28, 2012*

**English**

"Understanding the cause for Bartleby's reason to be an introvert and to offer polite refusals when asked to do something would suggest he deserves either sympathy or disdain." Thank You Ms. Sue, That was my thesis for a paper and I need to reword it, could you ...

*November 28, 2012*

**English**

Could you help me rephrase this sentence? "Understanding the cause for Bartleby's reason to be non-social introvert and to offer polite refusals when asked to do something would suggest whether he deserves sympathy or disdain."

*November 28, 2012*

**English**

Could you help me rephrase this sentence? "Understanding the cause for Bartleby's reason to be non-social introvert and to offer polite refusals when asked to do something would suggest whether he deserves sympathy or disdain."

*November 28, 2012*

**history**

Do you think that the Korean War was merely a civil war in which the United States supported one side, or should it be considered an international war in which the United States used the United Nations to further its anticommunist policies?

*November 28, 2012*

**English-Native speakers**

I can't use that. It is paraphrasing :/ I'll leave it that way "than if they were conducted today"

*November 28, 2012*

**English-Native speakers**

Need help with one sentence structure. I don't know if I am going to be able to explain it good. It goes like this "the measures will have to be much more drastic than if they were conducted today" I need help with this part "than if they were conducted ...

*November 28, 2012*

**math**

4 different ways

*November 27, 2012*

**Physics**

A cubical object of sides 5 cm is immersed completely in water. What is the force of buoyancy on the object? (Assume g = 10 m/s2)

*November 27, 2012*

**science grade 8**

Please, help. I need to create a comic that illustrates and explains what life would be like without 2 organ systems: muscular and digestive. I have an idea for digestive (you can live without gallbladder). I need to explain what is happening inside and outside the body, and ...

*November 22, 2012*

**psychological statistics**

Create a sample frequency distribution for one of the variables. Choose either a simple or grouped frequency distribution and explain your choice

*November 19, 2012*