Arora
Popular questions and responses by Arora
Math  Cubes
Consider a cube of side 100cm. Consider two diaganolly opposite points (the main body diagnol) as A and B. The cube is kept flat on the ground, and is filled with water upto a 40cm height. Now, the cube is tilted such that AB is vertical. What's the height
asked on December 29, 2017 
math
When an airplane leaves the runway, its angle of climb is 24° and its speed is 345 feet per second. How long will it take the plane to climb to an altitude of 10,000 feet? 16,000 feet? (Round your answers to one decimal place.) 10,000 ft = ? in s 16,000
asked on October 20, 2016 
Inorganic Chemistry
Which one is more stable, [PCl4]+ or [PCl6] ? Why? I'm thinking it has something to do with the fact that the former is tetrahedral and the latter is octahedral, but I'm not sure. Does that affect stability?
asked on December 4, 2017 
Geometry
Hi, so i reallllyy need help, i have an assignment that i have to complete, but the thing is theres a file and this site doesn't allow links, so does anyone have email to help me if you can help i will greatly appreciate it i'll email you the file. btw
asked on February 11, 2015 
science
whats the celstial sphere?
asked on April 6, 2010

Algebra 2 Probability
In a binomial distribution, the probability of the event happening (and not happening) must remain constant in all trials. This occurs when the removed card is replaced, and not when the removed card remains unreplaced.
posted on April 17, 2018 
math
Step 1: Make a frequency distribution table. I will refer to each of the values (number of cars) as x(i) and each of the frequencies as f(i) Step 2: Finding the mean: Mean = Σ( x(i)*f(i) ) / (Total number of salespersons)
posted on April 17, 2018 
Calculus
Yes, D is the correct answer.
posted on April 17, 2018 
BIO
Loss of body heat is a function of surface area per unit volume. The higher an organism's volume, the higher its metabolic activity and internal heat production. The higher an organism's surface area, the quicker it loses heat to the atmosphere (humans do
posted on April 17, 2018 
Computer
I don't know much about programming, but I don't believe that "calculate the percentage of a student" is the full question.
posted on April 17, 2018 
Math
 0.4 * n ≤ 6.8 Divide both sides by 0.4:  n ≤ 17 Multiply both sides by 1: (Note that multiplying or dividing by a negative number changes the direction of the inequality) n ≥ 17
posted on April 17, 2018 
Math
Assuming that the food drive lasted only two weeks, Number of cans collected in the second week = c The total number of cans must be more than 410: 185 + c > 410 Simply to obtain an inequality for c.
posted on April 17, 2018 
Physics HELP
Induced emf =  (Rate of change of magnetic flux) =  (Change in magnetic flux)/(Change in Time) =  d(Ф)/dt =  (Final magnetic flux  Initial Magnetic Flux)/0.5 =  (B*A*cos(θ2)  B*A*cos(θ1))/0.5 =  B*A( cos(θ2)  cos(θ1) )/0.5 Your question gives
posted on April 17, 2018 
math
z^2  4z + 5 = 0 (Note that the square of i is equal to 1) (2 + i)^2  4(2 + i) + 5 = 4 + (i^2) + 4i  8  4i + 5 = 4  1  8 + 5 = 9  9 = 0 Hence, yes, it is a solution.
posted on April 17, 2018 
Math
Do you mean: 2(y + 1) = 2 ? In that case: 2(y + 1) = 2 Divide by two on both side (y + 1) = 1 y + 1 = 1 Subtract one from both sides y = 0
posted on April 16, 2018 
Differential equations
Note that in a linear differential equation, the y' term is not supposed to have any coefficient. Hence, you must turn the differential equation into this form. [1/(x^2+1) * y'] + xy = 3 Multiply the whole equation by (x^2 + 1) y' + [x*(x^2 + 1)]*y = 3(x^2
posted on April 13, 2018 
Math. Can someone check my answer
Slope = (y2  y1)/(x2  x1) = (10 + 5)/(9 + 2) = (5)/(7) = 5/7 The correct answer is C. Always try to recheck your work. If you imagine the given points on the cartesian plane, you will see that they are on a line moving upwards, which must therefore
posted on April 12, 2018 
Mathematics
The longest straight line in this case is given by the diagonal of the rectangle. You can find its length by using the Pythagorean theorem. x^2 = (2.2)^2 + (1.2)^2 Solve for x.
posted on April 12, 2018 
Math
Yes, D is correct.
posted on April 12, 2018 
Chemistry
For finding an unknown molarity of a substance in a titration, we use the following formula: (M1 * V1) / (M2 * V2) = (n1 / n2) Where, M1 = Molarity of chemical 1 M2 = Molarity of chemical 2 V1 = Volume of chemical 1 V2 = Volume of chemical 2 n1 =
posted on April 12, 2018 
Ap Chemistry
Write down the reaction: NaCl + Ag(+) > AgCl + Na(+) The main thing to note here is that 1 mol of NaCl reacts completely with 1 mol of silver to form the required product. How many moles of Ag do we have? (It will be equal to the number of moles of
posted on April 12, 2018 
Math
Original oil = 550 l How much was sold? Twofifths of 550 l = (2/5)*550 = 2*110 = 220 l How much remained? 550  220 = 330 How much of the remaining was poured out? Onefifth of the remaning = (1/5)*330 = 66 Finally, how much remained? 330  66 = 264
posted on April 11, 2018 
Algebra
Usually, you would input x as 0 (to find intersection on the yaxis) and y as 0 (to find intersection on the xaxis) However, the graph of xy = 12 is a rectangular hyperbola. It does not meet either of the coordinate axes. Numerically, When x = 0, 0*y =
posted on April 11, 2018 
Algebra
It will cross the yaxis when x = 0 y = 2(0) + 6 y = 6 It will cross the xaxis when y = 0 0 = 2x + 6 2x = 6 x = 3 Yes, you are correct.
posted on April 11, 2018 
math
5 is V 40 is XL 5:40 am > V:XL am 6 is VI (There is no symbol for '0' in the roman numeral system) 6:00 pm > VI:00 pm
posted on April 11, 2018 
Math pre algebra
You need not mention the 'zero and,'. You can directly state the given number as 'twentyfive hundredthousandths'.
posted on April 11, 2018 
Physics
(I shall use the Cartesian Sign Convention) Object distance = u =  60cm Focal length = f = + 20cm (The focal length of a converging lens is taken as positive) Image distance = v As per the lens formula, (1/v) = (1/u) + (1/f) (1/v) = (1/20)  (1/60) v = 30
posted on April 10, 2018 
linear systems
y = 8x  14 y = x^2 + 4x  10 From these equations, you get: 8x  14 = x^2 + 4x  10 4x  4 = x^2 x^2  4x + 4 = 0 (x  2)^2 = 0 x  2 = 0 x = 2 So, the xcoordinate of the solution is 2. You can simply plus this into either equation to find the
posted on April 9, 2018 
Chemistry
Bolaji, the molecular mass of the given compound is NOT 512. The compound calcium phosphate should be written as Ca3(PO4)2, and has a mass of 310 u. You do not multiply the masses of calcium and phosphate, this is not an algebraic equation. You add the
posted on April 9, 2018 
math
Based on the answer I gave to your previous question, what would (fg)(x) mean?
posted on April 9, 2018 
math
This answers this question and the next: (f + g)(x) means that you have to add both f(x) and g(x). (f + g)(x) = x^2 − 36 + x^3 + 2x^2 − 10 (You have to simplify this) Similarly, (f * g)(x) means that you have to multiply f(x) and g(x).
posted on April 9, 2018 
Physics
Refractive Index = (Speed of light in vacuum)/(Speed of light in medium) Speed of light in vacuum = 3 x 10^8 m/s Refractive Index = 1.33 1.33 = (3 x 10^8)/(x) Solve for x.
posted on April 6, 2018 
Circuits 2
Most attenuation will occur when the current is highest. For an LCR circuit, as is given, this occurs at the condition of resonant frequency. For the required condition, ω = 1/(√LC) Plug in the values of L and C.
posted on April 3, 2018 
College Algebra
Assuming the given expression is n(t) = n(0) * e^(0.15t), Given: In the year 1995, t = 0 n(0) = 20 a) t = 10 n(t) = n(0) * e^(0.15t) = 20 * e^(0.15*10) = 20 * e^(1.5) b) n(t) = 400 n(t) = n(0) * e^(0.15t) = 20 * e^(0.15*t) 400 = 20 * e^(0.15*t) Solve for
posted on April 3, 2018 
Math
Yes, one of the angles turns out to be 78.5 degrees.
posted on April 3, 2018 
Math
This requires the dimensions of the tiles, which requires the given diagram.
posted on April 3, 2018 
algebra
Area of the rectangle = Product of the sides = (6 * 8) square ft = 48 sq ft Area of the square = Square of the side length = s^2 (Taking s as the side length) This is equal to the area of the rectangle. So, s^2 = 48 s = √48 s = 4√3 ft
posted on April 3, 2018 
math
Use the distributive property: (∛x +2)(∛(x^2)2∛x +4) = (∛x)(∛(x^2)) + 2(∛(x^2)) + (∛x)(2∛x) + 2(2∛x) + 4(∛x) + 4*2 (When the same base with different exponents is multiplied, the exponents are added, also, ∛x = x^(1/3), ∛(x^2) =
posted on April 3, 2018 
Science
The inference you can make this reaction is that Aluminum oxide is a basic oxide, because it forms a salt upon reacting with a base. (Do keep in mind, however, that Al2O3 is amphoteric. From this reaction, you can only infer its basic nature)
posted on April 2, 2018 
Science
Only the xylem parenchyma is living, the answer is A.
posted on April 2, 2018 
chemistry
The first step that takes place in the amide formation reaction, is that the :NH3 molecule (the semicolon represents the lone pair) donates its lone pair to the carbon atom (which is connected to the oxygen atom), forming a bond. The more electrophilic
posted on March 30, 2018 
chemistry
The reason the test works is because the Fe(3+) ion formed reacts with the benzoate ion formed to give a coloured solution. However, in an excess of alkali, the Fe(3+) ion instead reacts with the OH() ions in order to form ferrous hydroxide, which
posted on March 30, 2018 
Tourism
A characteristic of personality is that its core remains mostly stable throughout a person's life even in the presence of changing situational factors. However, it is also dynamic in the sense that an individual can show a wide range of traits to adapt to
posted on March 29, 2018 
Physics
C, Disassemble the nucleus (into its individual protons and neutrons)
posted on March 29, 2018 
Math
We need all values of x for which y is positive or zero. So, x²6x+9 is either positive or zero. x²6x+9 ≥ 0 x²6x ≥ 9 (x  3)^2  9 ≥ 9 (x  3)^2 ≥ 0 x  3 ≥ 0 x ≥ 3
posted on March 29, 2018 
MATH
(a  b)^n = Sum of all [(1)^r]*(nCr)*(a^r)*[b^(nr)] Where 'r' varies from 0 to n. a = 2 b = (1/4)x n = 4 r = 0,1,2,3,4 Plug in the values, sum it up.
posted on March 29, 2018 
Math
Yes, b is correct.
posted on March 27, 2018 
Math
Probability that a student is x inches tall = (Number of students who are x inches tall)/(Total number) In this case, the total number is the sum of all individual frequencies, which is 28 The number of students who are 52 inches tall = 6 Probability that
posted on March 27, 2018 
math
John's age = x Age in three years = Three times as old as today (x + 4) = 3*x x + 4 = 3x 4 = 3x  x 4 = 2x x = ?
posted on March 27, 2018 
Maths
Cost of one box = 2800 Cost of 40 boxes = 40 * 2800 = 112000 Discount = 4% of 112000 = 0.04 * 112000 = 4480 Amount paid = Price  Discount = 112000  4480 = ?
posted on March 27, 2018 
Mathematics
Interest = Final  Initial = 1344  1200 = 144 Interest = Principal amount * Rate * Time 144 = 1200 * 0.06 * t 144/(1200*0.06) = t 144/72 = t 2 = t The time is two years.
posted on March 26, 2018 
Math
hog = h(g(x)) = h(x+3) = √(x+3) The term in the square root cannot take negative values. It must be greater than (or equal to) zero. x + 3 >= 0 x >= 3 x =< 3 Hence, the domain of x is given by (∞, 3]
posted on March 25, 2018 
Calculus
Length of billboard = x Width of billboard = (100/x) Length including margin = x + 4 + 4 = (x+8) Width including margin = (100/x) + 2 + 2 = (100/x + 4) The total area is given by: (x+8)*(100/x + 4) = 100 + (800/x) + 4x + 32 = 4x + (800/x) + 132 This is the
posted on March 25, 2018 
Chemistry (concentration)
Is there any specific portion in these questions you do not understand? You've posted quite a few problems without any of your attempts to solve them.
posted on March 24, 2018 
Chemistry
204 grams of sugar dissolve in 100 g of water. => 1 gram of sugar dissolves in (100/204)g of water => 612 grams of sugar dissolves in 612*(100/204)g of water
posted on March 24, 2018 
Math
You require two digits, the sum of which is 14. These digits satisfy that property: 7,7 6,8 8,6 5,9 9,5 Put each of them into your final number, and you will get five such numbers. 2277 and 2268 are two, there are three more.
posted on March 24, 2018 
Math
Total marbles = x Red = (1/4)x Green = (1/8)x Yellow = (1/8)x Your question is missing a word in the part 'he brought 18 more marbles than' Take the difference of whichever colour has 18 more marbles than red, and solve for x.
posted on March 24, 2018 
college physics
c = Frequency * Wavelength c = Speed of light = 3 * 10^8 m/sec Input each frequency and the corresponding wavelengths will give you the wavelength range.
posted on March 23, 2018 
math
If you've been asked to determine the intersection by 'plotting accurate graphs', then it seems like you're expected to plot the given equations on graph paper, and then check the x and y coordinates of the point of intersection on your graph, rather than
posted on March 22, 2018 
Calculus
Radius = r Area = 4π(r^2) As per the question: dr/dt = 3ft/min dr/dt = 3 When t = 4, r = t*3 = 4*3 = 12 ft d(Area)/dt = d(4π*r^2)/dt = 4π*2r*(dr/dt) Plug in r = 12, dr/dt = 3, you'll get the answer (in feet squared per minute)
posted on March 22, 2018 
Maths
d[X]/dt = (0.001)*[X] => d[X]/[X] = (0.001)*dt Integrating both sides, ∫(1/[X])*d[X] = (0.001)*∫dt => log[X] = 0.001*t + C Now, the question says that when t = 0, X = W => log[W] = 0 + C = C Putting this value of C in the original equation, log[X] =
posted on March 22, 2018 
Calculus
For the parametric equation: dy/dt = 1 dx/dt = 5 So, dy/dx = (1/5) This is the slope of the tangent to the line with the given parametric equation. So, m = (1/5) Pointslope form of a line: (y  y') = m(x  x') (y  4) = (1/5)(x  6) y = (1/5)x + 14/5 You
posted on March 22, 2018 
Calculus
Consider: r = the radius of the tank R = the radius of the combined sphere k, k' = constants Volume of the layer of ice = Volume of the large sphere  Volume of the small sphere = (4π/3)*(R^3  r^3) Now, it's given that the rate of decrease of this volume
posted on March 20, 2018 
science
Energy stored in a capacitor = E = (1/2)*C*(V^2) => V = √((2*E)/C) As per the question, E = 5 * 10^4 J C = 3.3 * 10^3 Plug in the values to get 'V'
posted on March 20, 2018 
Math
The perimeter of a figure is the sum of the lengths of all its sides. The rectangle given to you has four sides. Two are of length 23 yards, and two are of length 14 yards. Perimeter = 23 + 23 + 14 + 14 = 46 + 28 = 74 yards
posted on March 19, 2018 
Physics
Change in potential energy = Kinetic Energy m*g*h = (1/2)*m*(v^2) 9.8 * 2.5 * 2 = v^2 49 = v^2 v = 7 m/s
posted on March 18, 2018 
math
[(x^24)/(4x)] * [(12x^4)/(x+2)] = [(x2)(x+2)/(4x)] * [(12x^4)/(x+2)] = [ (x2)(x+2)(12x^4) / (4x)(x+2) ] = [ (x2)(12x^4) / (4x) ] = [ (x2)(12x^3) / 4 ] = [ (x2)(3x^3) ]
posted on March 17, 2018 
Maths
If you mean: (5x) / (x^2 + 1), Then it depends entirely on what value of 'x' you take. For x = 0, the two terms are equal. For x = 1, (5x) / (x^2 + 1) is greater than one. For x = 1, (5x) / (x^2 + 1) is less than one.
posted on March 17, 2018 
Math
Your matrices are correct. As for determining the total expenditure, multiply both the matrices together. If you multiply a 2*3 with a 3*1 matrix (in that order), the product will be a 2*1 matrix. It will have two entries, each giving you the total
posted on March 17, 2018 
math
Original price = 75 (Can be approximated, it doesn't change the answer) Supermart: First discount = 25% of 75 = 0.25*75 = 18.75 , Cost = 75  18.75 = 56.25 Second discount = 15% of 56.25 = 8.43 , Final Cost = 56.25  8.43 = 47.8 Follow the same procedure
posted on March 17, 2018 
math
3 dozen eggs = 3 * 12 eggs = 36 eggs 25% of 36 = (25/100)*36 = (1/4)*36 = 9 9 broke, how many are left?
posted on March 17, 2018 
math
sina = (1/2) cosa = √( 1  (sina)^2) = (√3)/2 tana = sina/cosa = 1/√3 tan2a = (2tana/(1(tana)^2) Plug in the value of tan(a).
posted on March 17, 2018 
ALGEBRA 1!!!! PLS HELP!!!!
Four consecutive integers: x, (x+1), (x+2), (x+3) As per the question, 3*[x + (x + 2)] = 4(x+3) + 44 3(2x + 2) = 4x + 12 + 44 6x + 6 = 4x + 56 Solve for x.
posted on March 16, 2018 
Math
What type of graph are you dealing with? This really can't be solved without the graph. However, this may help: 1. A graph represents a linear relationship when the function varies linearly with the variable, that is, when the graph is a straight line.
posted on March 14, 2018 
science
Yes, A is correct.
posted on March 14, 2018 
Math
The lengths of both edges in similar rectangles have equal ratios. => (Length 1)/(Length 2) = (Width 1)/(Width 2) => 12/x = 10/15 => x = (12*15)/10 Solve for x.
posted on March 13, 2018 
School
Two complementary angle sum up to give 90 degrees. Angle 1 = x Angle 2 = (5/8)x x + (5/8)x = 90 Solve for x
posted on March 13, 2018 
Science
Which conditions?
posted on March 12, 2018 
math
Interest = Principal amount * Rate * Time = 1000 * 0.03 * 6 Total = 1000 + Interest
posted on March 11, 2018 
physics
F = k * (q1 * q2) * (1/r^2) Where k is a constant = 9 * 10^9 q1 and q2 are the individual charges, and r is the distance between them. When you plug in the given values, you will get an equation of the type: q1 * q2 = something Combine this with (q1 + q2 =
posted on March 10, 2018 
Physics
Your first step, is that you consider the electric field across the plates of the capacitor. When you take any small charge = dq from one plate of the capacitor to another, work will be done due to the presence of this electric field. That work is
posted on March 10, 2018 
maths
Area of margin = Area of bigger rectangle including margin  Area of picture Area of bigger rectangle = (50 + 2.5 + 2.5) * (30 + 2.5 + 2.5) = 55 * 35 Area of picture = 50 * 30 Area of margin = (55*35)  (50*30)
posted on March 10, 2018 
MATH
1/(1738000+h) = 3.599*10^7 => 1 = (3.599*10^7) * (1738000 + h) => 1/(3.599*10^7) = (1738000 + h) Now, 1/(3.599*10^7) = (10/3.599)*10^6 = 2.778*10^6 => 2.778*10^6 = (1738000 + h) => 1738000+h = 2.778550*10^+6 Feel free to reply with any doubts you may
posted on March 9, 2018 
Science
6. For this one you can consider the example of Snapdragon. Codominance is when both phenotypes are expressed. A mixture of redcolour genes and whitecolour genes would lead to pink colouration. 7. This is an autosomal recessive disease. So, both parents
posted on March 9, 2018 
AP Physics
Rotational Kinetic Energy = Work done by torque = (1/2)*(Moment of inertia)*(Final angular Velocity)^2 Convert rotations per minute to radians per second, plug in that value along with the value of the Moment of inertia (rotational inertia) and solve for
posted on March 7, 2018 
Physics
You can use the following equation of motion: v = u + at v is 0, since the vehicle comes to a stop. u is given to be 70m/s t is 2 seconds Solve for a. You will get a negative value, which implies deceleration.
posted on March 7, 2018 
Chem
PV = nRT => n = PV/RT, where n = number of moles Volume = 1.99L Pressure = 1 bar Temperature = 273.15 K Remember to take the value of R which corresponds to all these units. Use the above equation to solve for 'n'. Number of molecules = n * Avogadro's
posted on March 7, 2018 
precalculus
cotxsinx  cosx + cosx Putting in cotx = (cos/sinx), (cosx/sinx)*sinx + ( cosx + cosx) = cosx*(sinx/sinx) + 0 = cosx*1 = cosx
posted on March 7, 2018 
Chemistry
These links may prove to be useful. https://www.thetruthaboutforensicscience.com/gcmsmachineknowtheresdrugblood/ https://www.labcompare.com/MassSpectrometry/154GasChromatographMassSpectrometerGCMSInstrument/
posted on March 7, 2018 
Chemistry
The mass of Y is 1.5 times the mass of X in the compound, as per the percentages. If both molecules had the same atomic mass, they would also be present in this ratio in the compound. However, the atomic mass of X is twice that of Y. So, for the same mass,
posted on March 7, 2018 
math
Age of Mwenda = x Age of Mwenda's sister = y i) x = (3/5)*y ii) (x  20) = (2/5)*(y  20) Now, put 'x = (3/5)y' into the second equation. => ((3/5)*y  20) = (2/5)*(y  20) Solve for y, then for x.
posted on March 7, 2018 
math
5*(x + 10) + x = (5*x) + (5*10) + x = 5x + 50 + x = 6x + 50 Multiplication distributes across brackets.
posted on March 6, 2018 
Algebra 2 (Recursive Rule)
Partly correct, it should be a(n) = a(n1)  13.8, not a(n) = a(n+1)  13.8 This is because a(n) is given by subtracting 13.8 from the number *before* it, which is a(n1)
posted on March 5, 2018 
math
Mass of one book in kg = Total mass (in kg) / Number of books = 2.82/6 Mass of one book in g = Mass in kg * 1000
posted on March 4, 2018 
Science
Molarity = Number of moles / Volume (in liters) = 0.0285 / 0.050
posted on March 4, 2018 
MATH
Distance = Speed * Time Speed = 60 km/hr Time = Time between 8:55 AM to 10:10 PM = 13 hours and 15 minutes = 13.25 hours (15 minutes are a quarter of an hour) Distance = Speed*Time = 60*13.25
posted on March 3, 2018 
math
1) f(x) = x  x^2 When the determinant (b^2  4ac) of a quadratic is negative, it will have nonreal zeros. This is true for f(x)  (1/2) 2) No In order to get i^x = 1, x must be four, or some multiple of four (could also be negative because 1/1 is equal
posted on March 2, 2018 
Differential Equations
The equation should be: x' + y' = x  y => y' + (1)y = (x  x')
posted on March 2, 2018 
Differential Equations
x'=y+t y'=xt Add these two equations, you get: x' + y' = x  y y' + (x')y = x That gives you a linear differential equation of the form: y' + Py = Q Considering that P is the derivative of x, it'll make things easy while solving for the integrating
posted on March 2, 2018