Thursday
August 25, 2016

Posts by Scott

Total # Posts: 1,218

math
that is the number for all correct (or incorrect) see the answer to your other posted question
August 24, 2016

math
(a) it is a normal distribution (bell curve)n with the most likely score being half right (or wrong) you could plot the points using your binomial distribution from part (b) (b) the exponents in an individual term should sum to 15 only your last term does that otherwise, looks...
August 24, 2016

Chemistry
H₃BO₃ is triprotic (3 H⁺ per molecule) 29.15 * .025 = M * 3 * 25.0
August 23, 2016

Algebra
x (7 - 2x) (12 - 2x) = 33 4x³ - 38x² + 84x - 33 = 0 (9 - √15) / 2
August 23, 2016

Physical science check my answers
4. traveling a greater distance in the same amount of time means you went faster/slower?
August 23, 2016

Chemistry
a dm^3 is a liter two chloride ions per calcium chloride molecule .04 * .45 * 2
August 22, 2016

solid mensuration
π r² = 452 ... r = 12 the triangle formed by the chord and the radii from the ends has a central angle of 120º so 2/3 of the circle (240º / 360º), plus the area of the triangle; is the area of the larger segment
August 21, 2016

Physics
A. 239 = ½ * 3.7 * t² B. v = a t = -3.7 * t ... t is from part A
August 21, 2016

Physics
A. t = 50 ft/s / 32.2 ft/s² B. the velocity is zero at the peak ... so the average ascending velocity is 25 ft/s ... the displacement is 25 ft/s multiplied by the time from part A C. the time is half of the time from part A ... the average velocity is (50 + 25)/2 ft/s...
August 21, 2016

Algebra
you are correct (-11)^2 would be 121
August 21, 2016

Math
W = H + 4 L = W + 8 = H + 4 + 8 = H + 12 A = 2H (W + L) = 2 H (2H + 16) 512 = 4 H² + 32 H 128 = H² + 8 H 0 = H² + 8 H - 128 solve for H, then substitute back to find W and L
August 21, 2016

trigonometry
11π / 12 corresponds to a 15º reference angle in Q II 15º is half of 30º use a half-angle identity to find the exact value
August 20, 2016

Physics
the man is twice as far from the fulcrum as the rock so the effort is half the weight of the rock
August 20, 2016

PHYSICS topic is pressure
it is the lowered PARTIAL PRESSURE of oxygen, coupled with the increased PP of carbon dioxide that causes problems
August 20, 2016

PHYSICS topic is pressure
a deep well allows for little air circulation and the components of the atmosphere can stratify to a certain extent oxygen (which we need to breathe) is not the densest component the noble (inert) gas, argon, makes up about 1% of air; and is the heaviest as already mentioned, ...
August 20, 2016

SCIENCE
see the physics question 3 above yours
August 20, 2016

Maths Algebra
b = g + 334 b + g = 572 substituting ... g + 334 + g = 572
August 20, 2016

Trig
a sine value of .5 means a 30º reference angle in Q III, the angle is ... 180º + 30º = x
August 20, 2016

Maths Algebra
3/5 = 24/40 1/4 = 10/40 1/8 = 5/40 1/40 is left for foot travel 1/40 j = 2 km ... j = 80 km
August 19, 2016

Maths Algebra
9 is 1/4 of 1/2 of the herd 1/8 h = 9
August 19, 2016

Algebra
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August 17, 2016

Math
46 divided by 1
August 17, 2016

Physics
the kinetic energy of the ball at launch equals the gravitational potential energy at the peak ½ m v² = m g h v = √(2 g h) = √(2 * 9.8 * 20) m/s
August 17, 2016

Trigo
the length of belt that passes over the pulleys is the same 18 * 2π * 6 = 5 * 2π * r
August 17, 2016

Science
yes
August 17, 2016

Math
the force is proportional to the area 30 N / 50 cm² = f / 1500 cm²
August 16, 2016

mathematics
30000 = x [1 + (.12/12)]^(5 * 12) 32500 = y [1 + (.12/12)]^(7 * 12) 36000 = z [1 + (.12/12)]^(10 * 12) find x, y, and z and add them together log(3000) = log(x) + 60 log(1.01) log(3000) - [60 log(1.01)] = log(x) 10^[log(x)] = x
August 16, 2016

maths
12 is the common denominator for 6, 3, and 4 10/12 - 8/12 + 15/12 = 17/12 = 1 5/12
August 16, 2016

Math
3/5 men...so 2/5 women the difference (1/5) equals 12 5 * 12 = ?
August 16, 2016

Maths
torque = force * distance 200 Nm = f * .40 m
August 16, 2016

PreCalc
you want the sin⁻¹ function on your calculator sin⁻¹(0.65) = Θ = .7076 , 2.4340
August 15, 2016

Math
8+{4 x [(2+7) / 3]} = 20
August 15, 2016

PHYSICS/SCIENCE
a third as much as 15.0 g
August 13, 2016

Math
x² + 7x + 12 = 0 (x + 3) (x + 4) = 0 x = -3 , x = -4
August 13, 2016

Physics/Science
150 cal to take the water to 0º C 79.7 cal/g to freeze it
August 13, 2016

Math
c = 3.5 x + 10
August 12, 2016

Math-Direct Variation
x = k y 3 = k * 6 ... k = 1/2 x = 1/2 * 2/3 = 1/3
August 12, 2016

probability statistics
between means ... 4000 < n < 7000 3 choices for the 1st digit ... 4, 5, 6 8 for the 2nd digit 7 for the 3rd digit 6 for the 4th digit numbers = 3 * 8 * 7 * 6
August 12, 2016

statistics
there are 11 letters 3 of them occur twice possible arrangements equal ... 11! / (2! * 2! * 2!)
August 12, 2016

Calculus
velocity is dx/dt integrating gives position t/42 = dx/dt t/42 dt = dx integrating ... t²/84 = x = 100/21
August 10, 2016

math
there are 9C4 ways of selecting four printers there are 5C4 ways of selecting four good printers the probability is ... 5C4 / 9C4
August 10, 2016

Science
the simplified range equation is ... Rmax = v² / g ... 100 = v² / g ... 100 g = v² when an object is thrown straight up, the initial kinetic energy becomes gravitational potential energy ... ½ m v² = m g h ... v² / (2 g) = h combining the two ...
August 8, 2016

math
b + c = 45 / 2.5 = 18 kph b - c = 39 / 3.25 = 12 kph adding equations (to eliminate c) ... 2 b = 30 kph solve for b substitute back to find c
August 7, 2016

chemistry
a mole contains Avogadro's number of particles 5 moles = 5 * 6.02E23
August 7, 2016

Geometry
90º - a = (180º - a) / 5 450 - 5a = 180 - a 270 = 4a
August 7, 2016

Algebra/Quadratic Functions
the minimum lies on the axis of symmetry x min = -b / 2a = -(-200) / 2*2 = 50
August 7, 2016

Calc
f(x) = x^2+(1000-x)^2 ... = x² + 1E6 - 2000x + x² ... = 2x² - 2000x + 1E6 the minimum is on the axis of symmetry at x=500 ... the function increases from there so as x increases (below x=500), the function decreases f(0) = 0² + (1000 - 0)² = 1000²...
August 7, 2016

Math calculus
s.a. = 6 s² da/dt = 12 s ds/dt v = s³ ... 8 = 2³
August 7, 2016

Maths
M = 2R M + 11 + R + 11 + 3 = 75 Roy's dessert ... 11 + 3 = $14 3R + 25 = 75 ... R = 50/3 Roy's meal ... $50/3
August 7, 2016

Science
f = 1500 * g * .2
August 6, 2016

maths
4 (1 / 2 μf) = 1 / Ce Ce = 2 μf / 4
August 6, 2016

Math
d = h cot(32º) d - 8 = h cot(43º) 8 = h [cot(32º) - cot(43º)] h = 8 / [cot(32º) - cot(43º)]
August 6, 2016

Math
3/5 = 6/10 ... so there were 6 groups of boys the 2/5 of the class that were girls resulted in 2 groups of 1/5 each an aside ... the girls' groups were twice as large as the boys' groups
August 5, 2016

physics
don't know if significant figures are an issue but there are two in the data, and four in the result
August 5, 2016

Science
the horizontal velocity is the total velocity multiplied by cos(30º) at the topmost point, there is no vertical velocity ... so the K.E. is ... E cos²(30º)
August 4, 2016

Algebra
nancy starts with $50 more, but annie can save $5 more per week 50 / 5 = 10 weeks
August 4, 2016

physics
h = ½ g t² + 30 t = -4.9 t² + 30 t substitute 20 for h to find the time ... use the quadratic formula the time of max h is on the axis of symmetry of the parabola ... t = -b / 2a = -30 / -9.8 ... plug in the time to find h max the velocity is zero at max h the...
August 4, 2016

physics
average velocity = distance / time = 42 m / 2 s = 21 m/s average velocity = (initial + current) / 2 gravity slowed the arrow for 2 sec ... current = initial - (2 * 9.8) (Vi + Vi - 19.6) / 2 = 21 m/s solve for Vi time up = time down flight time = 2 (Vi / g)
August 4, 2016

Math
5 pies means 20 quarters (5*4) 3 quarters per neighbor means 6 neighbors, with two quarters left over 3*6 = 18 ... 18 + 2 = 20
August 4, 2016

I need help - precalc
1/√3 is the tangent of 30º or π/6 ... this is the reference angle -1/√3 is the tangent of the reference angle in quadrants II and IV so the x-values are ... 5π/6, 11π/6, and 17π/6
August 4, 2016

Math
no it is three decimal places to the right, so it is one thousandth the value of the 1st five (10^-3)
August 4, 2016

math
you could say "a" percent is like "a" peanut...one it doesn't use the term "percentage" regardless, the question is not well worded (1.01 n) * .20 = 400
August 4, 2016

biology
the high specific heat will help keep the pond from becoming a "fish stew"
August 4, 2016

Biochemistry
pOH = 14 - pH = 2.5 [OH⁻] = 1.0E-2.5 = .0032 M 1.75 * .0032 = .0056 moles of KOH multiply by the molar mass to find the quantity required
August 3, 2016

chemistry
.250 L of a .1 M solution contains .025 moles of solute mass needed is ... .025 * 204.23 g
August 3, 2016

Chemistry
in general; the lower the elevation, the higher the atmospheric pressure but the pressure (barometric) varies with weather conditions B might be the best answer for this somewhat ambiguous question
August 3, 2016

math order of operations
PEMDAS parentheses, exponents, multiplication, division, addition, subtraction 2*2*3 = 12 12/12 = 1 10 - 1 = 9 9*7 = 63 10 + 63 = 73
August 3, 2016

Chemistry
volume is inversely related to pressure (Boyle's Law) P1*V1 = P2*V2 108 * 8 = 224 * V2
August 3, 2016

math
it's in two steps 700 is the start of the 1st step, 7.5% for 6 years ... the result becomes the start of the 2nd step, 8.25% for 4 years
August 3, 2016

Physics
the horizontal pulling force is ... 260 cos(30º) the vertical pulling force is ... 260 sin(30º) the coefficient of sliding friction is ... [260 cos(30º)] / ... {450 - [260 sin(30º)]}
August 3, 2016

Math
it could be a looong summer... there are an infinite number of solutions if n and m are the numbers ... n - m = 3¼ , or , n = m + 3¼ m can be ANY mixed number
August 2, 2016

statistics
2.15 is .85 below the mean this is .85/.5 s.d. (1.7) use a z-score table to find the fraction of the population in this range about .045
August 2, 2016

I need help please - Pre-Calc
1/√2 is the cosine of 45º (π/4) ... that is the reference angle -1/√2 is the cosine of ... ±3π/4 ... add or subtract multiples of 8π/4 to find the values on the interval x values...-13π/4, -11π/4, -5π/4, -3π/4, 3π...
August 2, 2016

Physics
a = f / m a = [108.1 - (10 * g)] / 10
August 2, 2016

Physics
f = m a f = 3 kg * (25 m/s / .10 s)
August 2, 2016

Math
4 - $2 1 - $5 1 - $10 1 - $50
August 2, 2016

Chemistry
the molar mass of silver chloride is 143.32 g the molar mass of silver is 107.87 g so the mass of silver in the processed sample is ... .2865 * 107.87 / 143.32 the processed mass divided by the original sample mass is the purity of the original sample
August 2, 2016

science
zero
August 1, 2016

physics
a boy uses a slingshot to launch a rock with a velocity of 30m/s how long does it take it to reach a height of 20m,what maximum height does the rock reach, what is the velocity of the rock at this height, what is the velocity of the rock just before it lands
August 1, 2016

physics
the required takeoff speed for a large airplane is 180mi/hr(80m/s)the plane is capable of accelerating at a rate of 4m/s^2 assume the plane starts at rest, determine the minimum runway length required for this plane to safely take off, a smaller airplane requires a takeoff ...
August 1, 2016

math
a. v = x (8 - 2x) (15 - 2x) b. x must be less than 4 (the point where the 2nd factor goes to zero)
July 30, 2016

Chem
CaS ... calcium sulfide
July 30, 2016

Chem
increasing the temperature (adding energy), will drive the reaction to the left
July 30, 2016

math
AC ... y = -2 x + 20 BD ... y = 1/2 x D (8,4) BD = √(64 + 16) AD = √(9 + 36) area ABD = ½ √(80 * 45) = 30 area ABEF = 10² = 100
July 30, 2016

math
a graphical solution seems the most straight forward B(0,0) C(10,0) E(10,10) A(5,10) F(0,10) find the equation for AC, and then the equation for BD D is the intersection of the lines calculate the lengths of BD and AD to find the area of ABD
July 30, 2016

statistics
the failure rate is 15% the probability of both bulbs being bad is ... .15 * .15
July 29, 2016

Chemistry
C₃H₈ + 5 O₂ --> 3 CO₂ + 4 H₂O 4 moles of C₃H₈ would normally produce 12 moles of CO₂ ... but there is insufficient O₂ the O₂ is 1/5 of what is necessary, so the yield will be ... 1/5 * 12 moles
July 29, 2016

Science
the Earth completes one revolution in 24 hr so, how long is the 40th parallel? the "rotational" radius is equal to the radius of the Earth times cos(40º) the length of the parallel (circumference) is 2π times the radius divide the circumference by 24 hr to ...
July 29, 2016

math
Steve is referring to the 5-12-13 Pythagorean triple
July 28, 2016

math
S * L = 60 S² + L² = (S + 8)² S² + (60 / S)² = (S + 8)² S² + (3600 / S²) = (S + 8)² S⁴ + 3600 = S⁴ + 16 S³ + 64 S² S³ + 4 S² - 225 = 0 S = 5
July 28, 2016

Chemistry
1.2E24 / 6.0E23 = 2.0 moles 4.0 moles are added
July 28, 2016

Chemistry
there are 6.0 x 1E23 molecules in a mole 2.0 moles + 4.0 moles
July 28, 2016

math
d / r = t 240 / (b + 20) = 180 / b 240 b = 180 b + 3600
July 28, 2016

maths
1/2 of 1/6 is 1/12
July 27, 2016

pre cal
the 5th order term is the driver it is an odd power, so the function will have the same sign as x
July 27, 2016

Algebra 2
it would be infinite
July 27, 2016

@ Ms. Sue
the key here is "modern" humans (like us) Isaiah is using 6 million in some population growth scenario and getting weird results he's not interested in the start of the genus homo, he want to count people
July 27, 2016

Science
"modern" humans (us) arrived on the scene about 30 - 50 thousand years ago around the end of the last ice age there was limited interbreeding with the Neanderthals -- who were on the way out there have NOT been people like us around for 6 million years plug a ...
July 27, 2016

someone please help me. - Precalc
tan(90º - Θ) = cotan(Θ) cotan(Θ) = cos(Θ) / sin(Θ) [cos(Θ) / sin(Θ)] * sin(Θ) = cos(Θ)
July 27, 2016

Math
x (.20) + (300 - x)(.40) = 300 (.28) .2 x + 120 - .4 x = 84
July 27, 2016

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