Monday
April 27, 2015

Posts by Jai


Total # Posts: 1,756

phy
[Q1] Note that for an ideal gas, the volume of the gas is directly proportional to the temperature of the gas (Charles' Law). Just think of it as when you have a balloon of certain volume, and then you heated it (temperature increases), the balloon will expand (volume also...
July 3, 2013

chemistry
Assuming the gas is ideal, we use Charles' Law to relate the relationship between Temperature & Volume of gas: V1/T1 = V2/T2 where: T1 = initial temperature of gas (in K) T2 = final temperature of gas (in K) V1 = initial volume of gas V2 = final volume of gas substituting...
July 3, 2013

chemistry
Assuming the gas is ideal, we use Charles' Law to relate the relationship between Temperature & Volume of gas: V1/T1 = V2/T2 where: T1 = initial temperature of gas (in K) T2 = final temperature of gas (in K) V1 = initial volume of gas V2 = final volume of gas *note that to...
July 3, 2013

chemistry
Assuming the gas is ideal, we use Gay-Lussac's Law to relate the relationship between Temperature & Pressure of gas: P1/T1 = P2/T2 where: T1 = initial temperature of gas (in K) T2 = final temperature of gas (in K) P1 = initial pressure of gas P2 = final pressure of gas *...
July 3, 2013

Physics
Here, CSA of first rod = C CSA of first rod = D Thermal Conductivity of first wire = a Thermal Conductivity of 2nd wire = b Let the length of the two wires be L Temperature difference at the ends be ∆T Now by law thermal conduction for first conductor ∆Q/∆t...
June 3, 2013

math
Christamas card costs $0.75 each and postage stamps costs $0.39 each. If you have $3.00 only to spend on sending 2 cards to your friends, how much money will be left after sending the cards
April 24, 2013

Chemistry
N2 + 3 H2 -> 2 NH3 Just use their stoichiometric coefficients (number before the chemical's name) from the balanced chemical reaction to make ratios and solve for the unknown. In this case, 2 moles of NH3 are produced for every 3 moles of H2. Thus, 7.5 moles H2 x (2 ...
March 18, 2013

chemistry
Divide the mass given in the problem by the atomic weight of Copper from the period table. hope this helps~ :)
March 11, 2013

Math
First we represent the unknowns: Let x = daughter's present age Let 2x = mother's present age According to the problem, 20 years ago, the mother was three times older than her daughter. Thus, 2x - 20 = 3(x - 20) Solving for x, 2x - 20 = 3x - 60 2x - 3x = -60 + 20 -x...
March 6, 2013

math
Number of hours spent on studying = 4 Total number of hours (in a day) = 24 Percent of her day spent on studying is equal to: 4/24 * 100 = ? hope this helps~ :)
March 6, 2013

math
Yup that's right. :)
March 6, 2013

math
Percent of the theater filled is equal to the number of tickets sold over the total seats: 100/250 * 100 = ? hope this helps~ :)
March 6, 2013

Math
I think this problem has a figure given, but it can't be shown. Well I think it's ok. Acceleration is equal to change in velocity over time. Note that is a vector quantity, so it is represented by magnitude and direction. In the problem, since it slows down, it is ...
March 6, 2013

Math
I am a number on the hundreds chart. The sum of my digits is 9. My tens digit is 4. What number am I?
December 6, 2012

physics
Hello jai. (lol we're using the same name) :p Anyway, I think the statement is wrong that it forgot to mention the direction where the car travels. Velocity is equal to displacement over time, which is a vector quantity, thus it shall be stated using magnitude and ...
December 4, 2012

physics
Your friend says his remote control car travels at a velocity of 1.5 m/s. What is wrong with that statement
December 4, 2012

algebra
8y + 7x = -21 8y = -21 - 7x y = -21/8 - (7/8)x
October 20, 2012

math
C. less than eight
October 20, 2012

General Chemistry
What is the molality of a solution composed of 38.0 g of cane sugar (C12H22O11) dissolved in 175 g of water?
September 18, 2012

Algebra 2
14 + 3x – 7 = 7x + 7 – 4x 7 + 3x = 7 + 3x 0 = 0 It is ALWAYS true.
August 29, 2012

Physics
Tan(b)=31.4 /100
August 27, 2012

Please help quick! Maths
It's difficult to show here the graphical method, but there are many ways on how to do this. One way is to choose three random values of x (for example, 0, 1, and 2) and get the corresponding y value by substituting these values to both equations, and plot the points on a ...
August 26, 2012

Please help quick! Maths
It's difficult to show here the graphical method, but there are many ways on how to do this. One way is to choose three random values of x (for example, 0, 1, and 2) and get the corresponding y value by substituting these values to both equations, and plot the points on a ...
August 26, 2012

Please help quick! Maths
To do substitution method, we choose an equation and express one of the variables in terms of the other, and finally substitute this to the other equation. In this case, let's choose the first given equation and express x in terms of y: x - 2y - 5 = 0 x = 2y + 5 then we ...
August 26, 2012

College Algebra
1. fog(x) = 2 /[(7/x) - 3] simplifying, 2x/(7 - 3x) Domain: all real numbers except 3, 0 and 7/3 2. 2^(1-9x) = e^(2x) get ln of both sides: ln 2^(1-9x) = ln e^(2x) (1-9x)*(ln 2) = 2x (1-9x)/(2x) = 1/(ln 2) 1/(2x) - 9/2 = 1/(ln 2) 1/(2x) = 1/(ln 2) + 9/2 2x = 1/[1/(ln 2) + 4.5...
August 14, 2012

9th grade math
3 5/8 - 1 3/4 To do this, first we convert the mixed numbers to improper fractions. To convert we multiply the denominator (the number under the line) by the constant then add this answer to the numerator (number above the line), while retaining the denominator. Doing this, 3 ...
July 26, 2012

algebra
3x^3 + 9x^2 + 6x 3x(x^2 + 3x + 2) 3x(x+1)(x+2)
July 25, 2012

algebra
7z^2 + 21z - az - 3a 7z(z + 3) - a(z + 3) (7z - a)(z + 3)
July 25, 2012

chemistry
Heat of sublimation. It is approximately equal to 2850 J/g H2O.
July 24, 2012

math
2x(z - 1) + 8x 2xz - 2x + 8x 2xz + 6x
July 24, 2012

math
-8 1/8 = (6 1/2)p so first, we change the mixed numbers into improper fractions. To convert them, we take the product of the denominator and the constant then add it to numerator. This answer is the new numerator, while retaining the denominator: 8 1/8 = (8*8 + 1)/8 = 65/8 6 1...
July 17, 2012

practical math
assuming the gas is ideal, we can use the Charles' Law: V1 / T1 = V2 / T2 where V1 = initial volume of gas T1 = initial temp of gas V2 = final volume of gas T2 = final temp of gas substituting the values to the equation, 0.20 / 333 = V2 / 533 V2 = 0.20*533/333 V2 = 0.32 ...
July 17, 2012

Calc
f(x) = e^(−3x) + 5e^(4x) Note that the derivative of e^x is equal to e^x times the derivative of the exponent with variable x: d/dx (e^x) = e^x dx applying this, f'(x) = -3e^(-3x) + 20e^(4x) : First derivative f''(x) = 9e^(-3x) + 80e^(4x) : Second derivative
July 17, 2012

algebra 117
i interpreted it as: 3/(x^2 + x - 6) substituting x = 3, 3/(9 + 3 - 6) 3/6 1/2
July 17, 2012

math
2 log x - log 3 = 2 recall some laws of exponents. Note that we can rewrite the first terms as: 2 log x = log (x^2) Also, when two log terms of the same base are being subtracted, we can rewrite it as the quotient of the terms inside the log: log (x^2) - log (3) = log [(x^2)/3...
July 17, 2012

math
let x = your age 400 - 2x = 236 400 - 236 = 2x 164 = 2x x = 82
July 17, 2012

Math
I. 3x + 7y + 5 = 0 4x - 3y - 8 = 0 To solve, we can either use substitution or elimination method. For substitution, we choose one equation and represent one variable in terms of the other. Let's choose the first equation, and represent x in terms of y: 3x + 7y + 5 = 0 3x...
July 16, 2012

math30
substitute the value: pH = -log[H+] 2.5 = -log[H+] -2.5 = log[H+] note that log has a base of. Thus to get [H+], raise both sides of equation by 10 (to cancel the log): 10^(-2.5) = [H+] [H+] = 3.2 x 10^(-3)
July 11, 2012

algebra
*I had a correction for the last question you posted: Q: mang pedring wanted to construct a square table such that the length of its side is 30 cm longer than its height. What expression represents the area of the table? Suppose the table is 90 cm high what would be the area? ...
July 11, 2012

Integral math
Note that the given equation is a parabola that opens upward. The only point on the graph where the tangent line is parallel to the x-axis is at the vertex of the parabola, where it is at minimum. The slope of the tangent line at this point is zero (y=0). To get this point, we...
July 11, 2012

Integrated Math 1
f(x)g(x)= x^1999 * (2x - x^5) note that to multiply terms with the same base (in this case, the base is the variable x), we just add their exponents: 2*x^(1999+1) - x^(1999+5) 2x^2000 - x^2004 if it's just a typo, the answer is A. :)
July 11, 2012

Integrated Math 1
f(x) = -1 - 6x^2 - x^3 g(x) = -2 - 4x^2 f(x)-g(x) = -1 - 6x^2 - x^3 - (-2 - 4x^2) -1 - 6x^2 - x^3 + 2 + 4x^2 1 - 2x^2 - x^3 it's A. :)
July 11, 2012

algebra_correction
*wait. I had a correction: If table is 90 cm high, then the length of square is 120 cm. Substituting this to the equation for area, A = 90^2 + 60(90) + 900 A = 14400 cm^2 *sorry about that! The x value substituted must be 90, not 120. x__x ..haha wow ang galing naman,, fellow ...
July 11, 2012

algebra
Let x = height of table Let x+30 = length of table Recall that area of square is given by A = L^2 where L = length of one side. substituting, A = (x+30)^2 A = x^2 + 60x + 900 If table is 90 cm high, then the length of square is 120 cm. Substituting this to the equation for ...
July 11, 2012

algebra
probably the height in the problem is the length of the leg of the table or how high the table is.
July 11, 2012

algebra
*sorry i mean length = x + 30
July 11, 2012

algebra
Let x = height of the table since length is 30 cm longer than the height, then height = x + 30
July 11, 2012

trigonometry
First note that a whole circle measures 360 degrees or 2pi radians. The 3/2pi radians is just 3/4 of 2pi, Thus we can say that the length of arc given (the 60 ft) is just 3/4 of the circumference of the circle. If 60 is just 3/4 of the whole, then 60/(3/4) = 80 ft is the ...
July 11, 2012

algebra
let x = length of ladder if you draw the figure, you actually form a right triangle, where the ladder is the hypotenuse, and the wall is the height. Thus, we use trigonometry. sin (angle) = opposite / hypotenuse sin 75 = 34 / x x = 34 / (sin 75) x = 34 / 0.966 x = 37.27 ft ...
June 5, 2012

Pre-Calc/Math
recall that sin^2 x + cos^2 x = 1 therefore, we use this substitute the sin^2 x at the right side of equation: cos(x) + 1 = 1 - cos^2 x cos(x) = -cos^2 x cos(x) + cos^2 (x) = 0 factoring, cos(x) [1 + cos(x)] = 0 *for cos(x) = 0, the x values allowed are π/2 and 3π/2...
May 23, 2012

Math
Note that slope-intercept form is in the form y = mx + b where m = slope b = y-intercept Thus, y - 3 = -5(x + 1) y = -5x - 5 + 3 y = -5x - 2
May 23, 2012

Math
recall slope-point form: y - y1 = m(x - x1) where m = slope (x1, y1) = point on the line thus, y - 5 = 2(x - (-1)) y = 2(x + 1) + 5 y = 2x + 2 + 5 y = 2x + 7 hope this helps` :)
May 23, 2012

Math
recall slope-point form: y - y1 = m(x - x1) where m = slope (x1, y1) = point on the line thus, y - 5 = 2(x - (-1)) y = 2(x + 1) + 5 y = 2x + 2 + 5 y = 2x + 7 hope this helps` :)
May 23, 2012

6th g-math
let p = number of packs of mech pencil the total amount he could spend is 1.5p + 5.5 and this amount cannot be greater than (but can be equal to) $10, since his only money is $10. Thus, 1.5p + 5.5 _< 10 it's A.
May 23, 2012

Elem Math
Nope. Multiplying the lengths of sides gives you the volume. To get the surface area of a rectangular prism, SA = 2(L*W + L*H + W*H) where L = length W = width H = height therefore, #1. SA = 2(6*4.25 + 6*3.5 + 4.25*3.5) SA = 122.75 ft^2 #2. SA = 2(4*2.5 + 4*2.33 + 2.5*2.33) SA...
May 23, 2012

Precalculus
120 degrees and 300 degrees
May 23, 2012

science
first, write the chemical reaction: NH3 + H2SO4 -> (NH4)2SO4 then we balance this: 2NH3 + H2SO4 -> (NH4)2SO4 then we find the weight of NH3 and (NH4)2SO4. We can do this by getting each atomic mass of the element in the chemical formula, and add them. It can be found on ...
May 23, 2012

trig
let x = height of tree tan(angle) = x/27 tan(26) = x/27 x = 0.488*27 x = 13.17 = 13 m
May 23, 2012

algebra 1
(z - 4)/(z + 7) = 1/5 cross-multiplying, 5(z - 4) = z + 7 5z - 20 = z + 7 4z = 27 z = 27/4
May 23, 2012

Geometry
tan A * tan B = 1
May 23, 2012

math
sorry, i could not understand #15. #16. you have to plot this. But if you already know some properties of circle (in terms of its equation), you can skip plotting. The equation is a graph of circle, with center at (-6,-4) and radius = 6. The center is the position of source, ...
May 23, 2012

circles
At first, I was having difficulty understanding the given. I thought the PQ, PR and QR are the lengths of the triangle, but they are actually the arc (angle measure). Anyway, to get x, we know that the measure of a circle is 360 degrees. We get the sum of arcs PQ, PR and QR ...
May 23, 2012

math
3.62 x 10^7
May 23, 2012

circles and arcs
At first, I was having difficulty understanding the given. I thought the PQ, PR and QR are the lengths of the triangle, but they are actually the arc (angle measure). Anyway, to get x, we know that the measure of a circle is 360 degrees. We get the sum of arcs PQ, PR and QR ...
May 23, 2012

chemistry
recall that one mole of any substance is equal to Avogadro's number, which is 6.02 x 10^23 this number can be atoms, molecules, ions, etc. to get the number of moles, we just divide the given by the Avogadro's number: 2.8 x 10^20 / 6.02 x 10^23 = ?
May 23, 2012

algebra
[-16(x^7)(y^4)z]/[20(x^2)(z^3)] -4(x^5)(y^4)/(5z^2)
May 23, 2012

PHYSICAL SCIENCES
A. Argon all noble gases, except Helium, has eight valence electrons.
May 23, 2012

MATHS
that is true, if 'ln' is used, not 'log'. Well, in some books, ln and log seem interchangeable -they really mean ln, not log. If we rewrite the expression using ln, not log, e^(x + 3lnx) we can separate this into: (e^x)[e^(3lnx)] note that we can further ...
May 23, 2012

math
*sorry i mean x = 3/4
May 23, 2012

math
6 = 4x + 3 6 - 3 = 4x 3 = 4x x = 4/3
May 23, 2012

maths
work backwards: 2(2(2(2(0+1)+1)+1)+1) = 30 liters
May 22, 2012

Math
525
May 22, 2012

Math
let x = age of Travis let x-4 = age of Ellie (since Travis is four years older than Ellie) let 2(x-4) = age of Mac (since he is twice older than Ellie) since the sum of their ages is 44, x + x - 4 + 2(x - 4) = 44 2x - 4 + 2x - 8 = 44 4x - 12 = 44 4x = 56 x = 14 yrs old (Travis...
May 22, 2012

Math
recall that volume of cone is given by V = (1/3)*pi*(r^2)*h where r = radius which is half of diameter h = height and pi = constant equal to 3.14 substituting, V = (1/3)*3.14*[(5/2)^2]*7 now solve for V.
May 22, 2012

math algebra
let x = first number let x+1 = second number let x+2 = third number let x+3 = fourth number *note that there is +1 for every number since they are consecutive. therefore, x + x+1 + x+2 + x+3 = -2 4x + 6 = -2 4x = -8 x = -2 x+1 = -1 x+2 = 0 x+3 = 1 hope this helps~ :)
May 21, 2012

math trig
ln(2x-5) = 4 we raise both sides by e: e^(ln(2x-5)) = e^4 the e and ln will be cancelled, leaving only the 2x - 5: 2x - 5 = e^4 2x = e^4 + 5 x = (e^4 + 5)/2 hope this helps~ :)
May 21, 2012

math
Oh sorry. I thought it's outside. Nope, it can't be moved outside. 2^(x+1) = 9 2^(x+1) = 3^2 then we take the log of both sides: (x+1)*(log 2) = 2*(log 3) x + 1 = 2(log 3) / (log 2) x = [2(log 3) / (log 2)] - 1 or we can also rewrite the 1 as (log 2)/(log 2), so x = [2...
May 21, 2012

math
2^x + 1 = 9 2^x = 9 - 1 2^x = 8 then we rewrite 8 as power of 2: 2^x = 2^3 finally, since they have the same base (which is 2) we equate their exponents: x = 3 hope this helps~ :)
May 21, 2012

math
No. First to multiply fractions, we change mixed number into improper fraction. The mixed number here is 1 1/4. To change this, we multiply the denominator (the 4) to the constant (the first 1, not the 1 above the bar line) and add this to numerator. thus, 1 1/4 = (1*4 + 1)/4...
May 21, 2012

maths
recall these properties: -all sides of rhombus are equal. -the diagonals of rhombus are perpendicular (forms four 90 degree angles) -area of rhombus, if diagonals are given, can be calculated by A = d1 * d2 /2 where d1 & d2 are the diagonal lengths -side of a rhombus, if ...
May 21, 2012

maths
I think it has a typo. (what is "1nd")
May 21, 2012

algebra
for this problem, we will substitute the given to the equation p = mx + b, and then we solve simultaneously (two equations, two unknowns): 25 = 56m + b 20 = 66m + b to solve this, we can multiply one equation by -1 so that if we add the equations, the b will be cancelled: -25...
May 21, 2012

maths
let x = first number let 8-x = second number then we set up the equation. It says that the sum of their squares must be 34. thus, x^2 + (8-x)^2 = 34 then we solve for x: x^2 + 64 - 16x + x^2 = 34 2x^2 - 16x + 64 = 34 2x^2 - 16x + 30 = 0 x^2 - 8x + 15 = 0 since it's ...
May 21, 2012

maths
recall that an isosceles triangle has two equal sides. thus, to find this length, recall that the perimeter of a triangle is given by P = a + b + c but since two sides are equal, we can rewrite this as P = 2a + c substituting, 32 = 2a + 12 20 = 2a a = 10 now to find the area, ...
May 21, 2012

Geometry
recall that the volume of an oblique cone is given by V = (1/3)*(πr^2)*h where r = radius of circle (the base) h = height since diameter is equal to the height, we can say that h = d = 2r substituting, V = (1/3)π(r^2)(2r) 18π = (2/3)π(r^3) 18*(3/2) = r^3 27...
May 21, 2012

Algebra (re: %)
60/70 * 100 = 85.7%
May 21, 2012

Trigonometry
To combine the two log terms, first, the terms must have the same base (the number subscript of log). In this case, if there is no number subscript of log, the base is equal to 10. The two terms have the same base, 10. Now, recall that to combine log terms of the same base, *...
May 19, 2012

math
Let x = length of side of square thus area of square is A,square = x^2 recall that area of triangle is given by A,triangle = (1/2)b*h where b is the base and h is the height. The base and height of the triangle AMN are equal, which is (1/2)x. Thus, A,triangle = (1/2)*[(1/2)x...
May 19, 2012

algebra.
let x = width let 6x = length (according to the first statement) recall that area of a rectangle is given by, A = length x width thus, 54 = x * 6x 54 = 6x^2 9 = x^2 x = 3 ft (width) 6x = 18 ft (length) hope this helps~ :)
May 18, 2012

math
I think you mean, the ratio of the lengths of the smaller and larger cube. Recall that the surface area of a cube is given by SA = 6s^2 where s = length of one side then we get the length of one side of each cube. Larger: 32 = 6s^2 16/3 = s^2 s = 4/sqrt(3) Smaller: 18 = 6s^2 3...
May 17, 2012

math
I think you mean, the ratio of the lengths of the smaller and larger cube. Recall that the surface area of a cube is given by SA = 6s^2 where s = length of one side then we get the length of one side of each cube. Larger: 32 = 6s^2 16/3 = s^2 s = 4/sqrt(3) Smaller: 18 = 6s^2 3...
May 17, 2012

chemistry
first we write the chemical equation: C6H6 + O2 -> CO2 + H2O then we balance this: 2C6H6 + 15O2 -> 12CO2 + 6H2O then we solve for the molecular weight of C6H6. Note that mass of C = 12 and H = 1. thus, 6*12 + 6*1 = 78 g/mol then we get the number of moles of C6H6 used in...
May 16, 2012

chemistry
first we write the chemical equation: C6H6 + O2 -> CO2 + H2O then we balance this: 2C6H6 + 15O2 -> 12CO2 + 6H2O then we solve for the molecular weight of C6H6. Note that mass of C = 12 and H = 1. thus, 6*12 + 6*1 = 78 g/mol then we get the number of moles of C6H6 used in...
May 16, 2012

Geometry
*i mean 56 degrees.
May 16, 2012

Geometry
it's difficult to show solutions (because diagrams are required), but my answer is 58 degrees.
May 16, 2012

Chemistry
H2 + O2 -> H2O balancing this, 2H2 + O2 -> 2H2O then we find the limiting reactant. To determine the limiting reactant, we get the moles of product from the given moles of reactant. Whichever yield less number of moles of product is the limiting reactant. thus, 4 mol H2...
May 16, 2012

Math
270 degrees
May 15, 2012

math
(2x-5)/6 = (4x+1)/2 we must make the denominators same. to do this, we multiply the numerator & denominator of the term on the right by 3: (2x-5)/6 = 3(4x+1)/6 then we equate the numerators: 2x - 5 = 12x + 3 2x - 12x = 5 + 3 -10x = 8 x = -4/5
May 15, 2012

math 8th grade
multiply the given dimensions: 4 * 12 = 36 5 * 11 = 55 7 * 9 = 63 8 * 8 = 64 therefore, it's 8 in x 8 in.
May 14, 2012

math 8th grade
recall that area of rectangle (shape of the photo) is given by A = length * width substituting, A (original) = 3 * 5 = 15 if we triple both length and width, new length = 3 * 5 = 15 new width = 3 * 3 = 9 thus, A (new) = 15 * 9 = 105 to get the ratio, we divide the new area by ...
May 14, 2012

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