# boB

Popular questions and responses by boB-
## Economics

A monopoly firm faces a demand curve given by the following equation: P = $500 − 10Q, where Q equals quantity sold per day. Its marginal cost curve is MC = $100 per day. Assume that the firm faces no fixed cost. You may wish to arrive at the answers

*asked on May 3, 2016* -
## Chemistry

Assuming that sea water is a 3.5 wt % solution of NaCl in water, calculate its osmotic pressure at 20°C. The density of a 3.5% NaCl solution at 20°C is 1.023 g/mL.

*asked on April 13, 2010* -
## Pre Calculus

Find all $2 \times 2$ matrices $\bold{A}$ that have the property that for any $2 \times 2$ matrix $\bold{B}$, \[\bold{A} \bold{B} = \bold{B} \bold{A}.\]

*asked on September 20, 2017* -
## Chemistry

Balance the following equation for a half reaction that occurs in basic solution. Use e– as the symbol for an electron. SO3^2- ---> S2O4^2-

*asked on May 4, 2014* -
## Microecon help

Please help! Review for a test and am so lost! (1) An article in the New York Times (Oct. 18, 1990) described a successful marketing campaign by the French champagne industry. The article also noted that “many executives felt giddy about the

*asked on September 3, 2007* -
## LCM of two numbers?

lcm of two numbers pi/3 pi/2 How do I do it? Would it be pi or pi/6? Thanks

*asked on December 15, 2013* -
## math

I look at a random time of day at a digital clock (that shows times from 1:00 through 12:59). What is the probability that (ignoring the colon) I see a palindrome such as 8:08? Express your answer as a common fraction.

*asked on November 15, 2012* -
## Math

Of 30 students, 12 play football, 17 play soccer, and 5 play both, how many play neither?

*asked on March 12, 2013* -
## Algebra 2

Claire has borrowed $\$5,\!000$. She plans to pay off the loan in full after two payments. She will make one payment in 3 years, then another payment in 6 years. The second payment will be exactly double the amount of the first payment. How much is the

*asked on April 4, 2017* -
## Chemistry

In a particular redox reaction, MnO2 is oxidized to MnO4– and Cu2 is reduced to Cu . Complete and balance the equation for this reaction in acidic solution. Phases are optional. MnO2 + Cu^2+ ---> MnO4^- + Cu^+

*asked on May 4, 2014* -
## Chemistry

Which of the following ionic compounds has the highest melting point? Help: Lattice energy Select one: a. Cs2O b. K2O c. BeO d. SrO e. LiF f. CsI

*asked on November 10, 2014* -
## math

Three water pipes are used to fill a swimming pool. The 1st pipe alone takes 8 hours to fill the pool, the 2nd pipe alone takes 12 hours to fill the pool, and the 3rd pipe takes 24 hours to fill the pool. If all 3 pipes are opened at the same time, how

*asked on May 26, 2011* -
## geometry

The two non-parallel sides of an isosceles trapezoid are each 7 feet long. The longer of the two bases measures 22 feet long. The sum of the base angles is 140°. a. Find the length of the diagonal. b. Find the length of the shorter base. Round your

*asked on July 26, 2017* -
## Chemistry

Kc is 1.67 × 1020 at 25°C for the formation of iron(III) oxalate complex ion: Fe3+(aq) + 3 C2O42-(aq) [Fe(C2O4)3]3-(aq). If 0.0200 M Fe3+ is initially mixed with 1.00 M oxalate ion, what is the concentration of Fe3+ ion at equilibrium?

*asked on December 2, 2014* -
## Chemistry

The equilibrium constant, Kp, equals 3.40 for the isomerization reaction: cis-2-butene trans-2-butene. If a flask initially contains 0.250 atm of cis-2-butene and 0.145 atm of trans-2-butene, what is the equilibrium pressure of each gas?

*asked on December 2, 2014* -
## algebra 2

During the first part of a trip a canoeist travels 26 miles at a certain speed. The canoeist travels 8 miles on the second part of the trip at a speed 5 mph slower. Total time is 3 hours. What was the seed on each part of the trip

*asked on April 21, 2013* -
## math

Between which two consecutive integers does the radical square root of 15 lie?

*asked on September 4, 2019* -
## statistics

A university dean wishes to estimate the average number of hours his part-time instructors teach per week. The standard deviation is 2.6 hours. How large a sample must be selected if he wants to be 95% confident of finding whether the true mean differs

*asked on March 30, 2011* -
## Math

Katie makes 65% of her shots from the free throw line. Can you determine how many consecutive free throws she must make in order to increase her percentage to 68%? Explain.

*asked on July 2, 2016* -
## chemistry

The reaction: A + 3 B = D + F was studied and the following mechanism was finally determined A + B = C (fast) C + B = D + E (slow) E + B = F (very fast) The step with largest activation energy is a. the first step b. the second step c. the third step d.

*asked on February 24, 2012* -
## math

Anne wants to tie a support line from the top of a 50 foot radio tower to an anchor spot 30 feet from the tower’s base. Approximately how long will the line need to be?

*asked on June 20, 2013* -
## Math

A biologist has determined that a particular osprey has a 70% chance of catching a fish on any given day. Carry out a simulation of 20 trials using the random number table below to find the probability that the osprey will actually catch a fish on all of

*asked on May 20, 2014* -
## physics

a small bead can slide without friction on a circular hoop that is in a vertical plane and has a radius of 0.100 m. The hoop rotates at a constant rate of 3.00 rev/s about a vertical diameter. Find the angle beta at which the bead is in vertical

*asked on October 24, 2011* -
## Math

Peter bought 24 tickets for 490. Adult tickets =25 and student tickets = 15. How many of each type did he buy?

*asked on July 27, 2020* -
## Math, Please Help!!!

a hot air balloon is rising vertically 10 ft/sec while the wind is blowing horizontally 5ft/sec. Find the speed of the balloon and the angle x that it makes with the horizontal. I know that the speed of the balloon is the square root of (10)^2 + (5)^2, but

*asked on November 10, 2011* -
## Chemistry

a) Which of the following reagents would oxidize Zn to Zn2 , but not Ag to Ag ? Answers are: Co2+ Ca2+ Br2- Br2 Co or Ca b) Which of the following reagents would oxidize Ag to Ag , but not Cl– to Cl2? Answers are: Co Br- Br2 Co2+ Ca2+ or Ca

*asked on June 2, 2014* -
## geometry

the surface areas of two similar solids are 340 yd2 and 1158 yd2 the volume of the larger solids is 1712 yd3 what is the volume of the smaller solid?

*asked on May 30, 2013* -
## chemistry

Which of the following is not amphiprotic? a)H2O c)NH4+ e)all choices are amphiprotic b)HSO4 – d)H2PO4– need help!

*asked on March 17, 2012* -
## Chemistry

Calculate the total quantity of heat required to convert 25.0 g of liquid CCl4(l) from 25.0°C to gaseous CCl4 at 76.8°C (the normal boiling point for CCl4)? The specific heat of CCl4(l) is its heat of fusion is and its heat of vaporization is

*asked on April 13, 2010* -
## chemistry

Phosphoric acid is a triprotic acid, so H3PO4, H2PO4 -, and HPO4 2- are all acids. Which of the solutions below would have the lowest pH? 0.1 M NaH2PO4 0.1 M Na2HPO4 0.1 M Na3PO4

*asked on March 10, 2014* -
## math

two girls caught 25 frogs. Lisa caught four times as many as Jen did. how many frogs did Jen catch

*asked on February 3, 2011* -
## science

Two stones are launched from the top of a tall building. One stone is thrown in a direction 30.0degree above the horizontal with a speed of 10.0m/s ; the other is thrown in a direction 30.0degree below the horizontal with the same speed. Which stone lands

*asked on September 8, 2008* -
## Chemistry

How do you calculate ΔSfus and ΔSvap for HCl given melting point,ΔHfus, boiling point, and ΔHvap also how do you determine the entropy change when 5.20 mol of HCl(l) freezes at atmospheric pressure.

*asked on April 25, 2014* -
## Math

The entrance hall to the Louvre Museum in Paris is a glass and metal pyramid with a surface area of approximately 1980 square on each side . The base of the pyramid is a square that is 35.4 meters on each side. What is the slant height of the pyramid ?

*asked on April 2, 2014* -
## main ideas

Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect. A greenhouse used for plants stays warm because sunlight and heat coming through the glass roof are mostly trapped. The heat doesn't radiate back into the

*asked on September 6, 2013* -
## calculus

A square-based, box-shaped shipping crate is designed to have a volume of 16ft^3. The material used to make the base costs twice as much (per ft^2) as the material in the sides, and the material used to make the top costs half as much (per ft^2) as the

*asked on November 4, 2010* -
## Chemistry

An iron ore sample was dissolved in hydrochloric acid and the iron was obtained as Fe2+(aq). The iron solution was titrated with 38.54 mL of 0.471 M Ce4+ solution according to the balanced chemical equation below. Ce4+(aq) + Fe2+(aq) -> Ce3+(aq) +

*asked on March 11, 2009* -
## math

The table shows the number of people that went to see a movie last week. Use these statements to complete the table. On Thursday, 60% of the moviegoers were male. On Friday, 35% of the moviegoers were male. On Saturday, 70% of the moviegoers were female.

*asked on January 26, 2017* -
## Geometry :)

Use coordinate geometry to prove that the quadrilateral formed by connecting the midpoints of a kite is a rectangle. I have no Idea how to do this problem, so if anyone could help I would be very greatfull. :)

*asked on January 15, 2013* -
## Chemistry

40.0 ml of an acetic acid of unknown concentration is titrated with 0.100 M NaOH. After 20.0 mL of the base solution has been added, the pH in the titration flask is 5.10. What was the concentration of the original acetic acid solution? (Ka(CH3COOH) = 1.8

*asked on April 10, 2011* -
## physics

In the vertical jump, an Kobe Bryant starts from a crouch and jumps upward to reach as high as possible. Even the best athletes spend little more than 1.00 s in the air (their "hang time"). Treat Kobe as a particle and let ymax be his maximum height above

*asked on October 21, 2010* -
## Chemistry

What is the net ionic equation when H2SO4 is neutralized by NaOH in aqueous solution? Write the molecular equation. H2SO4 + 2NaOH ==> Na2SO4 + 2H2O Convert to ions. 2H^+ + SO4^= + 2Na^+ + 2 OH^- ==> 2Na^+ + SO4^= + 2H2O Now cancel those ions that appear on

*asked on February 17, 2007* -
## geometry

George plans to cover his circular pool for the upcoming winter season. The pool has a diameter of 20 feet and extends 12 inches beyond the edge of the pool. A rope runs along the edge of the cover to secure it in place. a. What is the area of the pool

*asked on July 26, 2017* -
## Calculus

Graph the function f(x)=x+4/x Graph the secant line that passes through the points (1,5) and (8,8.5) on the same set of axes Find the number c that satisfies the conclusion of the Mean Value Theorem for f on [1,8] c= Notice that if you graph the tangent

*asked on February 8, 2015* -
## Algebra

Participants in a study of a new medication received either medication A or a placebo. Find P(placebo and improvement). You may find it helpful to make a tree diagram of the problem on a separate piece of paper. Of all those who participated in the study,

*asked on May 21, 2014* -
## math

In a geometric series, t1=12 and s3=372.what is the greatest possible value for t5?

*asked on June 3, 2013* -
## Math

You invested $14,000 in two accounts paying 5% and 9% annual interest, respectively. If the total interest earned for the year was $820, how much was invested at each rate?

*asked on September 4, 2012* -
## Calculus

for the function F(t)=ln(t^2), let f(t)=F'(t). Write the integral from a to b of f(t) dt and evaluate it with the fundamental theorem of calculus. the integral from 1 to 3 ___ dt= __

*asked on November 30, 2011* -
## Operations Management

The maintenance department of a hospital uses 816 cases of liquid cleanser annually. Ordering costs are $12, carrying costs are $4 per case a year, and the new price schedule indicates that orders of less than 50 cases will cost $20 per case, 50 to 79

*asked on March 7, 2009* -
## geometry

What is the most precise name for quadrilateral ABCD with vertices A(–3, 2), B(–1, 4), C(4, 4), and D(2, 2)? 1. parallelogram 2. rhombus 3. quadrilateral 4. rectangle

*asked on January 11, 2013* -
## physics

two objects are thrown from the top edge of a cliff with a speed of 10 m/s. one object is thrown straight down and the other straight up. if the first object hits the ground in 4.0 second, the second hits the ground in ________ seconds after the first

*asked on August 9, 2012* -
## chemistry

Calculate the number of carbon atoms in 0.75 L of acetone (CH3COCH3). (density = 1.3 g/mL and boiling point = 48.5 degrees Celsius)

*asked on October 31, 2010* -
## math

Why couldn't the two elephants go swimming together?

*asked on March 17, 2009* -
## Chemistry

The following equation represents the decomposition of a generic diatomic element in its standard state. (1/2)X2(g)--->X(g) Assume that the standard molar Gibbs energy of formation of X(g) is 5.45 kJ·mol–1 at 2000. K and –64.30 kJ·mol–1 at 3000. K.

*asked on April 25, 2014* -
## Physics

A woman on a bridge 75.0m high sees a raft floating at a constant speed on the river below. She drops a stone from rest in an attempt to hit the raft. The stone is released when the raft has 7.00m more to travel before passing under the bridge. The stone

*asked on November 19, 2013* -
## Physics

When a wheel is rotated through an angle of 35 degrees, a point on the circumference travels through an arc length of 2.5 m. When the wheel is rotated through angles of 35 rad and 35 rev, the same point travels through arc lengths of 143 m and 9.0 X 10^2

*asked on November 19, 2008* -
## math

What set of reflections and rotations would carry rectangle ABCD onto itself? Rectangle formed by ordered pairs A at negative 4, 1, B at negative 4, 2, C at negative 1, 2, D at negative 1, 1.

*asked on September 17, 2018* -
## Data

Bridget works part time in a shoe store. Sometimes when it is not busy, she rearranges the shoes for fun. If she takes six different pairs of shoes and rearranges them in a row, in how many ways can she rearrange them so that no two shoes match? Is the

*asked on February 14, 2017* -
## physics

A plastic rod is rubbed against a wool shirt, thereby acquiring a charge of −4.9 µC. How many electrons are transferred from the wool shirt to the plastic rod? The elemental charge is 1.6 × 10−19 C.

*asked on March 10, 2015* -
## Physics

Work of 730 J is done by stirring an insulated beaker containing 80 g of water. What is the change in the temperature of the water? Please show calculation

*asked on October 19, 2011* -
## Chemistry

A 0.1300 g iron ore sample was dissolved in hydrochloric acid and the iron was obtained as Fe2+(aq). The iron solution was titrated with Ce4+ solution according to the balanced chemical reaction shown below. After calculation, it was found that 0.0259 g of

*asked on March 13, 2009* -
## Math

Terry bought some gum and some candy. The number of packs of chewing gum was one more than the number of mints. The number of mints was three times the number of chocolate bars. If gum cost 6 cents a pack, mints cost 3 cents each, and chocolate bars cost

*asked on June 6, 2020* -
## Chemistry

A chemist performs a series of reactions that produce binary lithium compounds. The elements include sulfur, chlorine, nitrogen, fluorine, selenium, oxygen, and iodine. The models below represent the ionic radii of compounds formed by reacting lithium with

*asked on April 13, 2020* -
## Geography

The acceptance of bribes by government officials who manage natural resources is an example of... A.profit maximization. B.productivity. C.environmental regulations. D.corruption. i chose A because that was in the book and it was false

*asked on November 23, 2019* -
## math

1. Which of the following numbers is a rational? A. 4/5 B. square root of 27 C. 4.02002000200002... D. Square root of 31 2. Which type of number is shown below? 0.313311333111... A. repeating decimal B. rational C. irrational D. terminating decimal 3.

*asked on September 21, 2016* -
## trig

An airplane is flying in the direction 148° with an airspeed of u = 920 kilometers per hour. Because of the wind, its groundspeed and direction are v = 820 kilometers per hour and 140°, respectively (see figure). Find the direction and speed of the wind.

*asked on November 2, 2015* -
## Chemistry Buffers

Write reactions showing how each of the following buffers would neutralize added HCl. HF and NaF Express your answer as a balanced chemical equation. Identify all of the phases in your answer. HC2H3O2 and KC2H3O2 Express your answer as a balanced chemical

*asked on November 16, 2014* -
## physics

Net force F causes mass m1 to accelerate at rate a. A net force of 3F causes mass m2 to accelerate at rate 2a. What is the ratio of mass m1 to mass m2?

*asked on November 5, 2013* -
## Math

Webster Aquatic Center offers various levels of swimming lessons year-round. The March 2005 Monday and Wednesday evening lessons included instructions from Water Babies through Adults. The number in each classification is given in the table that follows.

*asked on July 4, 2012* -
## Physics

A 1200-kg frictionless roller coaster starts from rest at a height of 24 m. What is its kinetic energy when it goes over a spot that is 12 m high?

*asked on May 10, 2012* -
## Economics

Suppose that some firms in a competitive industry are earning zero economic profits, while others are experiencing losses. All else equal, in the long run, we would expect the number of firms in the industry to A. increase. B. decrease. C. remain the same.

*asked on November 29, 2011* -
## Auditing

1. Which of the following matters would an auditor most likely consider to be a significant deficiency to be communicated to the audit committee? A. Management's failure to renegotiate unfavorable long-term purchase commitments. B. Recurring operating

*asked on March 11, 2010* -
## Chemistry

Use the dilution relationship (Mi x Vi = Mf x Vf) to calculate the volume of 0.500 M NaOH needed to prepare 500 mL of .250 M NaOH. This is my work ? L Solution = 500mL x (1L/1000mL) = .500L ? mol NaOH = .500 L Solution x (0.250 M NaOH/1 L Solution) = .125

*asked on February 28, 2009* -
## algebra

what is the value of 11x^-3y^-1 for x = -1 and y = 2?

*asked on March 3, 2019* -
## physics

A force acts on a 2kg mass and gives it an acceleration of 3 m/s^2. what acceleration is produced by the same force when acting on a mass of (1) 1kg? (2) 4kg? (3) how large is the force?

*asked on October 25, 2018* -
## Pre Calculus

For a vector $\bold{v}$, let $\bold{r}$ be the reflection of $\bold{v}$ over the line \[\bold{x} = t \begin{pmatrix} 2 \\ -1 \end{pmatrix}.\] [asy] unitsize(1 cm); pair O, V, R; O = (0,0); V = (3,1); R = reflect(O,(2,-1))*(V); xaxis(-2,4); yaxis(-3,1);

*asked on September 20, 2017* -
## Science

In a chemical compound, would you expect an oxide ion to be joined with one atom of calcium or one atom of potassium? Why?

*asked on January 12, 2017* -
## Math

In first gear, or low gear, an automobile's engine runs about three times as fast as the drive shaft. In second gear, the engine does not have to run as fast; usually it runs about 1.6 times faster than the drive shaft. Finally, in third, or high gear, the

*asked on June 17, 2013* -
## English II

On a proud round cloud in a white high night. A. alliteration B. consonance C. assonance D. limerick

*asked on May 1, 2013* -
## Math

A cattle train left Miami and traveled toward New York. 14 hours later a diesel train left traveling at 45km/h in and effort to catch up to the cattle train. After traveling for four hours the diesel train finally caught up. What was the cattle train's

*asked on October 23, 2012* -
## Physics B

A car slows down from 23 m/s to rest in a distance of 85m. What is its constant acceleration? I got -6.224, but a friend was telling me it's -3.11 and that I had to divide by 2. Why is that?

*asked on September 12, 2009* -
## Math

Scott Mason purchased a 5-unit apartment building as an investment before he retired. From the rent he collects each month, Scott pays out $1,025 for expenses. How much rent must he charge for each of the 5 apartments if he wants to make $450 profit each

*asked on September 6, 2019* -
## statistics

The distribution of B.A. degrees conferred by a local college is listed below, by major. Major Frequency English 2073 Mathematics 2164 Chemistry 318 Physics 856 Liberal Arts 1358 Business 1676 Engineering 868 9313 What is the probability that a randomly

*asked on April 16, 2015* -
## Math

A fence 12ft high runs parallel to a tall building at a distance of 2ft from the building. What is the length of the shortest ladder that will reach from the ground over the fence to the wall of the building?

*asked on December 13, 2014* -
## algebra

Find an equation of the line that satisfies the given conditions. Through (5, 3) and (4, 7)

*asked on October 24, 2014* -
## Trigonometry

The wheels of a scooter have a diameter of 4.5 inches. If the person riding the scooter is traveling down hill at 15.0 mph. what is the approximate angular speed of the wheels in radians per second

*asked on September 25, 2014* -
## english

Identify the italicized word according to its class in structural linguistics. (There) are no easy answers.

*asked on November 7, 2012* -
## chemistry

Consider the following reaction: CaCN2 + 3H2O ¨ CaCO3 + 2NH3 105.0 g CaCN2 and 78.0 g H2O are reacted. Assuming 100% efficiency, which reactant is in excess and how much is leftover? The molar mass of CaCN2 is 80.11 g/mol. The molar mass of CaCO3 is

*asked on October 31, 2010* -
## chemistry

express liquid pentanol and gaseous oxygen as a chemical reaction

*asked on October 8, 2010* -
## math

Farmer Brown had some animals. One-fourth were horses, one-half were cows, and the rest were pigs. He had 8 pigs. How many animals did he have altogether? I know you would get a common denominator for 1/4 and 1/2 which would be 4 so you would have 1/4+2/4=

*asked on February 4, 2009* -
## Algebra II

Maria and Zoe are taking Biology 105 but are in different classes. Maria's class has an average of 78% with a standard deviation of 5% on the midterm, whereas Zoe's class has an average of 83% with a standard deviation of 12%. Assume that scores in both

*asked on January 10, 2009* -
## Math, Geometry and Physics

An enemy ship is on the east side of a mountainous island. The enemy ship can maneuver to within 2500 meters of the 1800 meter high mountain peak and can shoot projectiles with an initial speed of 250m/sec. If western shoreline is horizontally 300 meters

*asked on January 16, 2007* -
## Physics

The density of copper is 8.96 g cm^−3 and its molar mass is 64 g mol^−1. Calculate the mass of 1 atom of copper.

*asked on July 11, 2020* -
## Statistics

50 employees in an office wear eyeglasses. 43 have single-vision correction, and 7 wear bifocals. If two employees are selected at random from this group, what is the probability that both of them wear bifocals? What is the probability that both have

*asked on October 2, 2019* -
## Chemistry

Green plants use light from the sun to drive photo synthesis. Photosynthesis is a chemical reaction in which water (H2O) and carbon Dioxide (CO2) chemically react to form the simple sugar glucose (C6H12O6) and oxygen gas (O2). What Mass of oxygen gas is

*asked on August 28, 2019* -
## chemistry

What is the mass of sodium needed to make 2 g of sodium oxide (4Na + O2 → 2Na2O)? Ar values: O = 16, Na = 23. please help I'm really struggling. also please try to explain it to the simplest form because I really don't understand.

*asked on March 14, 2019* -
## physics

A 1000 kg car traveling is at 40.0 m/ s. To avoid hitting a second car the driver slams on his brakes. The brakes provide a constant friction force of 8000 N. ( a) Find the minimum distance that the brakes should be applied in order to avoid a collision

*asked on November 12, 2017* -
## Pre Calculus

Let $\bold{w} = \begin{pmatrix} 2 \\ -1 \end{pmatrix}$. There exists a $2 \times 2$ matrix $\bold{P}$ such that \[\text{proj}_{\bold{w}} \bold{v} = \bold{P} \bold{v}\] for all 2-dimensional vectors $\bold{v}$. Find $\bold{P}$.

*asked on September 20, 2017* -
## Math

The sum of the three smallest positive values of theta such that 4(cos*theta)(sin*theta) = 1 is k*pi. Find k. Help!!!!!

*asked on June 26, 2016* -
## math

Each time the same letter appears it represents the same digit.Different letters represent different digits.C+C=D;D+E=17;A+2C=D;2B+C=8.Find the sum A+B+C+D+E

*asked on December 20, 2012*