Wednesday

June 29, 2016
Total # Posts: 7,799

**Probability**

The probability that it will take 5 or more flips of a fair coin before it lands on heads can be written as a/b , where a and b are coprime positive integers. Find a+b
*March 12, 2013*

**Chemistry**

I was given extra credit to find who Le Châtelier's High School Principal was. Not his PrincipLE, but his PrincipAL. My chemistry teacher told us only one student of his out of all these years came with the answer. Think outside of the box. Thanks.
*March 11, 2013*

**SCIENCE**

when a diorite partially melts, which element(1)............ decreases in the melt as a(2).......... magma forms. I have few options to choose from a)iron b)andesite c)rhyolite d)potassium f)basalt
*March 11, 2013*

**Math**

the median was 142 I forgot a number 142 is also on my list. thank you so much for your help
*March 10, 2013*

**Math **

Dr. Jane I came up with this: 127,128,129,139,139,139,141,143,144,145,146,147,148,152 Does this seem to work?
*March 10, 2013*

**math**

make up a set of 15 numbers with the following landmarks: maximum: 152 Range: 25 Mode: 139 Median: 142
*March 10, 2013*

**Geometry**

What is the minimum distance between any point on the circle x^2 + y^2 = 25 and the line y = -\frac{3}{4}x + \frac{75}{4} ?
*March 10, 2013*

**Geometry**

In the 2001 population census, information was collected about the number of people in each household, which is denoted by X. It is given that P(X=1) = 0.25, P(X=2) = 0.32, P(X=3) = 0.18, P(X=4) = 0.15, P(X=5) = 0.07, P(X=6) = 0.02 and P(X\geq 7) = 0.01. If R is the ...
*March 10, 2013*

**Geometry**

Martin's iPod has 24 songs on it. He wants to make a playlist consisting of three songs to dance to. Let N be the number of different playlists Martin can make. What are the last 3 digits of N?
*March 10, 2013*

**Calculus**

Evaluate \displaystyle \int_1^{10} \left(\sqrt{x} + 1\right)^3 dx - \int_1^{10} \left(\sqrt{x} - 1\right)^3 dx .
*March 10, 2013*

**Trigonometry**

If g(t) = 5t+1 and h(n) = 2(n - 7), what is the value of h(g(3))?
*March 10, 2013*

**Algebra**

Find the smallest positive integer N such that 13^N \equiv 1 \pmod{2013}.
*March 10, 2013*

**Physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10~m/s^2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?
*March 10, 2013*

**Calulus**

Given \displaystyle \int_0^{\frac{3\pi}{2}} x^2\cos x \, dx = a - \frac{b\pi^2}{c}, where a, b and c are positive integers and b and c are coprime, what is the value of a + b + c?
*March 10, 2013*

**chemistry help !!!!!!!!!!!!!!!!**

a)A N6+ ion in its ground state absorbs an X-ray photon of energy 2.0000 keV. Explain what happens to the ion and why. b)Explain why the nitrogen ion N6+ is a hydrogen-like ion. Assuming the ion is for the major stable isotope 14N, state which sub-atomic particles it contains ...
*March 10, 2013*

**SCIENCE**

when a diorite partially melts, which element(1)............ decreases in the melt as a(2).......... magma forms. I have few options to choose from a)iron b)andesite c)rhyolite d)potassium f)basalt
*March 9, 2013*

**Geometry**

Given a 100 by 100 square grid, what is the most number of 1 by 51 rectangles that we can cut out of it?
*March 9, 2013*

**Geometry**

ABCDE is a regular pentagon. FAD is an equilateral triangle, such that points F and E are on the same side of line AD. What is the measure (in degrees) of \angle FAB?
*March 9, 2013*

**Geometry**

How many perfect squares less than 1000 end with the digit 6?
*March 7, 2013*

**Geometry**

What is the minimum distance between any point on the circle x^2 + y^2 = 25 and the line y = -\frac{3}{4}x + \frac{75}{4} ?
*March 7, 2013*

**Trigonometry**

\sqrt{i} in polar form can be written as r(\cos \theta + i \sin \theta), where r is a real number and 0 \leq \theta \leq \frac{\pi}{2}. What is the measure of \theta (in degrees)?
*March 7, 2013*

**Algebra**

Out on my street, there are a certain number of pigeons sitting on telephone poles. If there were exactly 2 pigeons sitting on each telephone pole, then 1 pigeon would have no space to sit on. If there were exactly 3 pigeons sitting on each telephone pole, then there would be ...
*March 7, 2013*

**Algebra**

Out on my street, there are a certain number of pigeons sitting on telephone poles. If there were exactly 2 pigeons sitting on each telephone pole, then 1 pigeon would have no space to sit on. If there were exactly 3 pigeons sitting on each telephone pole, then there would be ...
*March 7, 2013*

**Algebra**

Out on my street, there are a certain number of pigeons sitting on telephone poles. If there were exactly 2 pigeons sitting on each telephone pole, then 1 pigeon would have no space to sit on. If there were exactly 3 pigeons sitting on each telephone pole, then there would be ...
*March 7, 2013*

**Calculus**

Evaluate \displaystyle \lim_{x \to 0} \frac{e^{44x} - 1}{x^2+2x}.
*March 7, 2013*

**Algebra**

Alan and Bob are playing with numbers. Starting with the number n=1 they take turns performing arithmetic manipulations with n. Alan goes first and always multiplies n by 3. Bob adds 1 or 2 to the number n, depending on a coin toss. A number is called reachable, if it can ...
*March 7, 2013*

**Algebra**

what is the smallest positive integer N such that 13^N \equiv 1 \pmod{2013}
*March 7, 2013*

**Algebra**

The difference of the cubes of two consecutive odd positive integers is 400 more than the sum of their squares. Find the sum of the two integers.
*March 7, 2013*

**Geometry**

Circles \Gamma_1 and \Gamma_2 intersect at 2 distinct points A and B. A line l through A intersects \Gamma_1 and \Gamma_2 at C and D, respectively. Let M be the midpoint of CD. The line MB intersects \Gamma_1 and \Gamma_2 again at E and F , respectively. If MA=129, MB =156 and...
*March 7, 2013*

**Geometry**

ABCD is a convex quadrilateral satisfying AB=BC=CD, AD=DB and \angle BAD = 75^\circ. What is the measure of \angle BCD?
*March 7, 2013*

**Geometry**

Two of the heights of a triangle are 63 and 147 . Given that the third height is also an integer, what is the maximum possible value for the third height?
*March 7, 2013*

**math**

I don't understand
*March 7, 2013*

**math**

thank you, Ms.sue
*March 7, 2013*

**math **

Mike is saving money for a new bike that costs $180.00. If m represents the amount of money he has saved so far, which expression represents the amount of money, in dollars, he still needs to save? a. 180 + m b. 180 - m c. 180 ' m d. 180 . m
*March 7, 2013*

**physics**

I child with a mass of 20kg,hops on a merry go round with moment of intertia of 1000kg and radius of 7m.if it takes the child time T to move 360degrees ,relative to the ground at 6m away from the center,what is the angle covered relative to the ground
*March 7, 2013*

**Chemistry**

A 1.00 kg gold bar at 1010 K is dropped into 0.750 kg of sand at 25 °C. Assuming no heat is lost to the atmosphere, what is the final temperature of the sand?
*March 7, 2013*

**Chemistry**

A 1.00 kg gold bar at 1010 K is dropped into 0.750 kg of sand at 25 °C. Assuming no heat is lost to the atmosphere, what is the final temperature of the sand?
*March 7, 2013*

**Calculus**

Given that \displaystyle \int_0^4 x^3\sqrt{9+x^2} dx = a, what is the value of \lfloor a \rfloor?
*March 7, 2013*

**Physics**

You launch a model rocket up into the sky. Right after launch the rocket is accelerating upwards at 10~m/s^2. What is the magnitude of the net force in Newtons on the rocket if the rocket has a mass of 0.1 kg?
*March 7, 2013*

**Geometry**

ABCD is a convex quadrilateral satisfying AB=BC=CD, AD=DB and \angle BAD = 75^\circ. What is the measure of \angle BCD?
*March 7, 2013*

**Geometry**

A circle \Gamma cuts the sides of a equilateral triangle ABC at 6 distinct points. Specifically, \Gamma intersects AB at points D and E such that A, D, E, B lie in order. \Gamma intersects BC at points F and G such that B, F, G, C lie in order. \Gamma intersects CA at points H...
*March 6, 2013*

**Geometry**

Let G be a rectangular grid of unit squares with 3 rows and 8 columns. How many self-avoiding walks are there from the bottom left square of G to the top left square of G?
*March 6, 2013*

**Physics**

What must the critical angle be if light transmits from diamond into water?
*March 6, 2013*

**Physics**

A racquet ball with mass m = 0.224 kg is moving toward the wall at v = 14.8 m/s and at an angle of è = 27° with respect to the horizontal. The ball makes a perfectly elastic collision with the solid, frictionless wall and rebounds at the same angle with respect to ...
*March 6, 2013*

**math**

simpplify. (3x)^3 (note use positive exponents only.) my answer is 27x^3
*March 5, 2013*

**language**

Those trees have (fewer, less) fruit on them.
*March 5, 2013*

**language**

Of the 2 swimmers, Dana is the (more better, best, better)
*March 5, 2013*

**Algebra**

What is \left \lfloor ( 3 + \sqrt{5} ) ^3 \right \rfloor?
*March 4, 2013*

**math**

please display graph of 2x=1 (if can be) thanks
*March 4, 2013*

**Algebra**

What are the sum of the roots of f(x) = x^2 - 16x + 63?
*March 4, 2013*

**Algebra**

The difference of the cubes of two consecutive odd positive integers is 400 more than the sum of their squares. Find the sum of the two integers.
*March 4, 2013*

**Algebra**

Find the number of integer quadruples (a,b,c,d) with 0\leq a,b,c,d \leq 100, such that a and b are the roots of the quadratic equation x^2-cx+d=0, while c and d are the roots of the quadratic equation x^2-ax+b
*March 4, 2013*

**Algebra**

x and y satisfy 2^x = 5 and 5 ^ y = 64. What is the value of xy?
*March 4, 2013*

**Algebra**

How many integer values of x are there such that |x-3| + 5 < 16 ?
*March 4, 2013*

**Algebra**

Alan and Bob are playing with numbers. Starting with the number n=1 they take turns performing arithmetic manipulations with n. Alan goes first and always multiplies n by 3. Bob adds 1 or 2 to the number n, depending on a coin toss. A number is called reachable, if it can ...
*March 4, 2013*

**Geometry**

How many ordered triples (a, b, c) of positive integers are there which satisfy the equation a + b + c = 10 ?
*March 4, 2013*

**Algebra**

Find the number of integer quadruples (a,b,c,d) with 0\leq a,b,c,d \leq 100, such that a and b are the roots of the quadratic equation x^2-cx+d=0, while c and d are the roots of the quadratic equation x^2-ax+b.
*March 4, 2013*

**Geometry**

ABC is a right triangle with AB = 2, BC = 8\sqrt{3} and AC = 14. What is the value of \sec \angle BAC?
*March 4, 2013*

**Calculus**

Given that \displaystyle \int_0^4 x^3\sqrt{9+x^2} dx = a, what is the value of \lfloor a \rfloor?
*March 4, 2013*

**Geometry**

A 12 by 12 by 12 cube has all its faces painted blue. It is then broken down to 1728 individual 1 by 1 by 1 cubes. The probability that a randomly chosen 1 by 1 by 1 cube has exactly 2 faces painted blue is \frac {a} {b} , where a, b are coprime. What is the value of a+ b?
*March 4, 2013*

**Algebra**

How many integers from 1 to 19999 have exactly 15 divisors?
*March 4, 2013*

**Algebra**

Alan and Bob are playing with numbers. Starting with the number n=1 they take turns performing arithmetic manipulations with n. Alan goes first and always multiplies n by 3. Bob adds 1 or 2 to the number n, depending on a coin toss. A number is called reachable, if it can ...
*March 4, 2013*

**Algebra**

The difference of the cubes of two consecutive odd positive integers is 400 more than the sum of their squares. Find the sum of the two integers.
*March 4, 2013*

**Hard physics**

Two equal point charges of 5 µC are on the horizontal axis. One charge is at -10 cm, the other is at +10 cm.? These two charges don't move, they are STUCK, take the potential to be zero at infinity. Find the potential at the following coordinates: (0,0) cm, (0,10)cm...
*March 3, 2013*

**algebra**

rachel and rosa each invested the same amount of money in bonds. Rachel got an 8% return on her money and rosa got a 9% return. If rosa's annual interest was $500 more than rachel's, how much did each invest? Do i need a chart for this problem?
*March 3, 2013*

**Chemistry**

what is the percent by mass of NaCHO3 in a solution containing 12g NaCHO3, dissolved in 450mL of water?
*March 3, 2013*

**Geometry**

Sandy has a long list of 100 suitors. She decides to label them according to if they are tall, dark or handsome. She finds that each of her suitors fall into at least one of the categories, and 65 of them are tall, 76 of them are dark and 53 of them are handsome. If 20 of the ...
*March 2, 2013*

**Physics**

train car with mass m1 = 521 kg is moving to the right with a speed of v1 = 7.9 m/s and collides with a second train car. The two cars latch together during the collision and then move off to the right at vf = 5.1 m/s. 1)What is the initial momentum of the first train car? I ...
*March 1, 2013*

**Geometry**

Luis has a simple calculator that has buttons for the digits 0 through 9, each of the 4 basic operations (+, - ,*,/ ), and an '=' button. Luis pushes a digit followed by the '+' sign, followed by another digit, followed by the '-' sign, followed by ...
*March 1, 2013*

**chemistry**

A 12 g sample of Ne is added to a container that also holds .78 mol of helium gas. What is the partial pressure of helium if the total pressure, after mixing is 2.43 atm?
*March 1, 2013*

**chemistry**

Propane reacts with oxygen in a combustion reaction. What volume of carbon dioxide gas is formed when 20 L of propane are reacted with 55.7 L of oxygen?
*March 1, 2013*

**math**

Three forces act concurrently on a point P as shown below. Which vector represents the direction of the resultant force on point P?data:image/png;base64,...
*March 1, 2013*

**Geometry**

In acute triangle ABC, we have \angle CAB = 34 ^\circ . E is the foot of the perpendicular from B to AC. A point H is on BE is chosen, and X is the foot of the perpendicular from H to AB. What is the measure (in degrees) of \angle of EHX?
*March 1, 2013*

**Physics**

Recently, Asteroid 2012 DA14 came within 34,200 km from the center of the earth at its point of closest approach. If the moon goes around the earth once every 27.5 days, what is the ratio of the distance of closest approach of DA14 to the radius of the orbit of the moon?
*March 1, 2013*

**Geometry**

ABC is an acute angle triangle with points D and E on BC and AC, respectively such that BE and AD are altitudes. AD and BE intersect at H. If \angle BCA = 39 ^\circ and \angle EBA = 2 \angle DAB , what is the measure of \angle ABC(in degrees)?
*March 1, 2013*

**Geometry**

Luis has a simple calculator that has buttons for the digits 0 through 9, each of the 4 basic operations (+, - ,*,/ ), and an '=' button. Luis pushes a digit followed by the '+' sign, followed by another digit, followed by the '-' sign, followed by ...
*March 1, 2013*

**Physics**

What current is produced by a ring with a radius of 0.5 m and a uniform positive linear charge density of 1 microCoulomb/m rotatingwith an angular frequency of 4π/s? a. 1 microAmpere b. 3.14 microAmpere c. 6.28 microAmpere d. 12.6 microAmpere
*March 1, 2013*

**Physics**

Suppose that you wish to fabricate a uniform wire out of 1 g of copper. (Resistivity = 1.72*10^-8 Ohm-m, density = 8.94*10^3kg/m^3). If the wire is to have a resistance of R = 0.5 ohm and all of the copper is to be used, how long is the wire? a. 1765 m b. 1816 m c. 1.8 m d. 0....
*March 1, 2013*

**Physics**

A current of 4.00 A flows through the heating element of heater converting 500 J of electrical energy into thermal energy every second. What is the voltage across the ends of the heating element? a. 2000 V b. 125 V c. 250 V d. 0.008 V e. 0.125 V
*March 1, 2013*

**English**

Can someone tell me if my sentences are correct, please? I'll be very thankful to you. •When I arrived at the hotel, someone was cleaning my room •If I had known that he was so rude, I would have never married him. •You would tell the truth if you were good ...
*February 28, 2013*

**English**

Can someone tell me if my sentences are correct, please? I'll be very thankful to you. •When I arrived at the hotel, someone was cleaning my room •If I had known that he was so rude, I would have never married him. •You would tell the truth if you were good...
*February 28, 2013*

**physics**

An MP3 player operates with a voltage of 3.7 V, and is using 0.14 W of power. Find the current being supplied by the player's battery.
*February 28, 2013*

**physics**

A police car has passed by you with its siren blazing (529-Hz) while traveling at 28.1-m/s. What frequency would you hear after it has passed by?
*February 28, 2013*

**Geometry**

Luis has a simple calculator that has buttons for the digits 0 through 9, each of the 4 basic operations (+, - ,*,/ ), and an '=' button. Luis pushes a digit followed by the '+' sign, followed by another digit, followed by the '-' sign, followed by ...
*February 28, 2013*

**Geometry**

ABC is an acute angle triangle with points D and E on BC and AC, respectively such that BE and AD are altitudes. AD and BE intersect at H. If \angle BCA = 39 ^\circ and \angle EBA = 2 \angle DAB , what is the measure of \angle ABC (in degrees)?
*February 28, 2013*

**Geometry**

The volume of a sphere is numerically equal to the surface area of the sphere. If this value is equal to N \pi, what is the value of N?
*February 28, 2013*

**Physics**

Recently, Asteroid 2012 DA14 came within 34,200 km from the center of the earth at its point of closest approach. If the moon goes around the earth once every 27.5 days, what is the ratio of the distance of closest approach of DA14 to the radius of the orbit of the moon?
*February 27, 2013*

**Geometry**

In acute triangle ABC, we have \angle CAB = 34 ^\circ . E is the foot of the perpendicular from B to AC. A point H is on BE is chosen, and X is the foot of the perpendicular from H to AB. What is the measure (in degrees) of \angle EHX?
*February 27, 2013*

**SCIENTIFIC NOTATION (ALGEBRA**

9.04 * 10 to the 9th power
*February 27, 2013*

**SCIENTIFIC NOTATION (ALGEBRA**

9.04 * 10^9
*February 27, 2013*

**Math**

Altogether 178 people attended the feast. There were 44 more men than women who came. How many men and how men women attended?
*February 27, 2013*

**History**

What was the biggest challenge that Abraham Lincoln faced while in office/
*February 27, 2013*

**Algebra**

f(x) is a polynomial such that f(1) = 8 and f(3) = 16. r(x) is the remainder when f(x) is divided by (x-1)(x-3). What is r(5)?
*February 26, 2013*

**math**

How long is a rectangular strip of land with a width of 5/4 km and an area of 3/4 square km ?
*February 26, 2013*

**Linear Algebra**

Prove that If a vector space is of dimension n and a set of vectors spans V, then that set of vectors must be linearly independent.
*February 26, 2013*

**Chemistry**

How many moles of NaOH are in 13.2 mL of 3.00 M NaOH?
*February 26, 2013*

**PLEASE COULD SOMEONE HELP ME OUT Physics**

Thank you Elena your a life saver :)
*February 25, 2013*

**PLEASE COULD SOMEONE HELP ME OUT Physics**

Two long straight aluminum wires, each of diameter 0.30mm, carry the same current but in opposite directions. They are suspended by 0.50m long strings...If the suspension strings make an angle of 3.0 degree with the vertical, what is the current in the wires? Thank you......
*February 25, 2013*

**Math**

B)The two ranges are close together, so there are probably no outliers in this set.-John McMuffin Sources: (Many calculators :D)
*February 25, 2013*

**PLEASE COULD SOMEONE HELP ME OUT Physics**

Hi Elena thank you, but this is what I did and i got it wrong sqrt(2π*5.23x10^-2*2700*π*2.25x10^-6*9.8/4*4π*10^-7)= 1.38x10^-4 but it is wrong what did i do wrong aluminum density is 2700 kg/m^3 and 2.25x10^-6 is .30 mm divided by 100 to get meters an then ...
*February 25, 2013*