Friday
August 26, 2016

Posts by steve

Total # Posts: 42,783

Chemistry
convert to moles, then multiply by Avogadro's Number
August 25, 2016

Math
see related questions below
August 25, 2016

Physics I - Modern
it's mv/√(1 - v^2/c^2) see http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html
August 25, 2016

Math
well, a 150lb person on the moon would weigh (150/120) * 20 = 25lb
August 25, 2016

Math
no idea. try google
August 25, 2016

physics
40 mi/hr * 1609m/mi * 1hr/3600s * 60s/min * 3min = 1073.7 m
August 25, 2016

7th grade math
clearly, two of the three possible discounts will give enough discount so that the final price with tax will be less than $25. So, probability is 2/3
August 25, 2016

7th grade math
There are 8 possible outfits with the shoes and bottoms. So, what is the smallest multiple of 8 that is at least 35? Using n tops, he gets 8n outfits.
August 25, 2016

Pre-calculus
Since the axis is horizontal, the general equation is x = a(y-k)^2 + h Since the vertex is at y=k, k = h and that means x = a(y-k)^2 + k Using the two points, we have a(-2-k)^2 + k = 6 a(4-k)^2 + k = 3 solve those, and you wind up with x = 1/4 (y-2)^2 + 2 x = 5/36 (y-14/5) + ...
August 25, 2016

math
1/4 + 5/8 + x + 3/4 = 2 1/2 Now just solve for x did you get 7/8 ?
August 25, 2016

Math
since distance = speed * time, if your speed is x, then 2*x + 2*2x = 258
August 25, 2016

physics
The ball's height is modeled by h(t) = 15t - 4.9t^2 The ball will be 8m high twice: on the way up and on the way down. These times can be found by solving 15t - 4.9t^2 = 8 See http://www.wolframalpha.com/input/?i=15t+-+4.9t%5E2+%3D+8 If you include the units in your ...
August 25, 2016

MATH
(36-30)/30 * 100
August 25, 2016

Maths
there are 48*16 food portions after 4 days, 48*4 portions have been eaten. So, there is enough for (48*16 - 48*4)/(48-12) = 16 days or, after 4 days, 1/4 of the food is eaten. That leaves enough for 12 days for the full population. But, the population is now 3/4 what it was, ...
August 25, 2016

value
m/d = 8/5 d = 15, so m=24 so, what is m-6?
August 25, 2016

Maths
start with cot(x/2) = sinx/(1+cosx) and see where you can take that.
August 25, 2016

maths
just list the factors of 72, and work with that, depending on how many piles you want: 1 72 2 36 2 2 18 2 2 2 9 ... 3 3 8 3 24 and so on
August 25, 2016

alg. Connections
total points for an 85 average: 85*3 = 255 Points so far: 81+86 = 167 So, haw many does she still need?
August 25, 2016

algebra HELP MRS SUE
B is better :-)
August 25, 2016

lauren
If $x at 11%, then the rest $(6300-x) is at 7%. So, just add up the interest: .11x + .07(6300-x) = 565
August 25, 2016

value
And surely the ratio is 4:3, not 40:3 maybe for bread 40:3 would be appropriate, as it is not so sweet as a cake.
August 25, 2016

Geometry
You may be right, but I have no diagram, so it's hard to say; but they do add up to 180°, so they are also supplementary.
August 25, 2016

maths
visit https://www.learnnext.com/nganswers/ask-question/answer/OPQR-is-a-rhombus-three-of-its-vertices-lie-on-the-circle-/Areas-Related-to-Circles/18625.htm
August 25, 2016

Science
1.5 m/hr * 1hr/3600s = 1/2400 m/s now, recall that time = distance/speed and use that what are you, a slug? Maybe you meant 1.5 km/hr. If so, jack up the speed by a factor of 1000.
August 25, 2016

math
well, just add the fractions: 1/4 + 1/3 + 1/2 + 7/12 + 3/4 + 5/6 + 1 = 3/12 + 4/12 + 6/12 + 7/12 + 9/12 + 10/12 + 12/12 = (3+4+6+7+9+10+12)/12 = 51/12
August 24, 2016

Math
assuming straight-line depreciation, then it will have lost (10/4)(.25) = .625 = 5/8 of its value So, it will be worth 3/8 of 21000 or $7875
August 24, 2016

Math - Composition of Functions
huh? really? g(x) = 1/x so, f(x) = g◦h = 1/h = 1/(x+1)
August 24, 2016

math
1xxx1 or 1xxx7 now just fill in the other 3 digits in the 6 ways possible
August 24, 2016

math
Hmmm. I see it as $54(1/6) + (1/2)($18(1/6)) = $12
August 24, 2016

Math
x y
August 24, 2016

Math
why are you guessing? I hope you actually did some kind of calculation. since cos(kx) has period 2pi/k, cos(pi/3 x) has period 6 the rate of change is y' = -pi/3 sin(pi/3 x) so, it is zero at pi/3 x = 0 or pi or 2pi; that is, x = 0,3,6 sin(pi/3 x) is at a max when pi/3 x...
August 24, 2016

physics vectors
the final vector will have x- and y-components. The direction θ is such that tanθ = y/x
August 24, 2016

physics vectors
so, get out your graph paper, plot the vectors and measure the final vector.
August 24, 2016

Math
12(3+2)
August 24, 2016

math
if the three numbers are x-1, x, x+1 then you know that x+1 = (x-1)/2 + 2 or x+1 = (x-1+2)/2 depending on how you parse the words
August 24, 2016

MATH - again?
Damon already did this one for you.
August 24, 2016

calculus
x^2+4y^2+16z^2−64 = 0 16z^2 = 64-x^2-4y^2 2z ∂z/∂x = -2x 2z ∂z/dy = -8y so, ∂z/∂x = -x/z ∂z/∂y = -4y/z ∂^2z/∂x^2 = -(x^2+z^2)/z^3 and you can do the others similarly, using the quotient rule or the product rule
August 24, 2016

math
subtracting a smaller number results in a greater difference.
August 24, 2016

Economics
Assuming that all the variable cost is labor, that would make wages for (50-30)/2 = 15 units
August 24, 2016

Math
note that this is also just (x+y)/2 + (7+17)/2
August 24, 2016

Math
(x+y)/2 = 10 (x+7 + y+17)/2 = (x+y + 24)/2 = (x+y)/2 + 24/2 = 10+12 = 22
August 24, 2016

business
total_grade=0fori=1to4readscore[i]totalgrade+=score[i]nextiaverage=total_score/4fori=1to4displayi,": ",score[i]nextidisplay"average: ",average
August 24, 2016

math
area is circumference times height, so 14πd = 396 assuming open ends.
August 24, 2016

math
not quite sure which direction 60°north and 45°east is supposed to be.
August 24, 2016

math
no idea what x is, but each leg is 145/√2
August 24, 2016

maths
120-(60+50-20)
August 24, 2016

math
see http://www.askiitians.com/forums/Trigonometry/prove-cot-a-cot-60-a-cot-60-a-3-cot3a_106221.htm for one solution. You might try proving it without recourse to sin and cos.
August 24, 2016

Kaplan
their combined speed is 67 mi/hr so, which two numbers differ by 9 and sum to 67? x-y=9 x+y=67 ...
August 24, 2016

Math
if you use your sum-to-product formulas, you will see that the results is a real number. imaginary part is zero
August 23, 2016

Math
you have a 7-24-25 triangle, in QII cosθ = x/r = -24/25
August 23, 2016

physics vectors
A+B = 2i-7j tanθ = -7/2 in QIV A-B = 4i+5j tanθ = 5/4 in QI
August 23, 2016

science
treating the vectors as complex numbers, we have 75i + 250 + 109cis(pi/6) - 156i = 344.4 - 26.5i or, in polar form, 345.4 @ E4.4°S
August 23, 2016

math help me out
does that mean p received 80% of the profit?
August 23, 2016

Maths
assuming simple interest, you want P*.25/2*4 = 8560*0.12*5 not quite sure what 25/2% means, but if I got it wrong, just fix it.
August 23, 2016

Algebra 1
not whole numbers rational integer
August 23, 2016

Math
1 ml, 20 ml, 979 ml Pick any three distinct numbers that add up to 1000
August 23, 2016

Math
just as you cannot subtract 7 from 2 in 32 - 17 you change 32 to 20+12 Now you can borrow the 7 from 12, leaving 15 2 hrs 2 minutes is the same as 1 hr 80 minutes. Now you can subtract from a number bigger than 20.
August 23, 2016

math
assuming you can draw tallies, just make the marks, usually in groups of 4 lines with a crossing line for 5. See https://www.google.com/search?q=tally+marks&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiljfC-xdjOAhVK6WMKHdHWDDoQsAQITA&biw=1541&bih=852
August 23, 2016

Algebra
flip each side and you have 1/x + 1/y = 1/6 6/x + 6/y = 1 6x+6y = xy Not sure just where you want to go with this. Clearly, 1/2 + -1/3 = 1/6
August 23, 2016

math data management
she needs at least 4 out of the remaining 8 questions correct. So, that has probability This topic is discussed here: http://math.stackexchange.com/questions/853407/4-heads-in-8-tosses
August 23, 2016

Educational Tech
input and output
August 23, 2016

Methametical literacy
she's 60 km ahead when he starts he's going 20km/hr faster. 60/20 = 3 hrs to catch up
August 23, 2016

math ASAP
x/(x+6) = 7/9 9x = 7(x+6) 9x = 7x + 42 2x = 42 x = 21 so, x+6 = 27
August 23, 2016

Math
see related questions below
August 23, 2016

Math
(5600*.95)*1.10 = .95p
August 23, 2016

math
6 = 2*3 so, 3 times as far as he went in 2 hours.
August 23, 2016

maths
since cos(a+b) = 0, a+b = pi/2 so, b = pi/2 - a and sin(a-b) = sin(a-pi/2+a) = sin(2a-pi/2) = -sin(pi/2 - 2a) = -cos(2a) or, since a = pi/2 - b = -cos(2(pi/2-b)) = -cos(pi-2b) = cos(2b)
August 23, 2016

Geometry
just use the distance formula for each segment.
August 23, 2016

Math
if the first vertex is at (1,0), then the others are at (cos 2kπ/7, sin 2kπ/7) for k=1..6
August 23, 2016

Math
$5.50 no matter how many hours. Now, if you want an hourly rate, well, duh -- divide the money by the time: $/hr
August 23, 2016

physics
series: R = 6 parallel: R = 1/6 Other arrangements will produce values in between those.
August 23, 2016

Maths
well, with those two roots, f(x) = (x+2)(x-3) so expand that and you can see what p and q must be.
August 23, 2016

Math
5 is 3 * 5/3 So, the distance is (5/3)(189)
August 23, 2016

algebra
google your question. Much faster than waiting around here: https://www.google.com/#q=metric+ton
August 23, 2016

Urgent help! Physics
Vx = v cosθ Vy = v sinθ h(t) = Vy*t - 5t^2 ball stops when h=0 ball has traveled Vx * t along the ground.
August 23, 2016

Algebra
n = 6+4 "exceeds" and "more than" indicate addition. See what you can do with q.
August 23, 2016

Math
2/5 + 1/5 + 1/x = 1 x = 5/2
August 23, 2016

Math
Just list the possibilities. You know there are 36 total outcomes. How many fit the conditions? R B R-B 1 1 0 1 2 -1 1 3 -2 2 1 1 2 2 0 2 3 -1 2 4 -2 ... 4 6 -2 Then divide the successes by the total of 36
August 23, 2016

Math
so, she picked 2*35 + 15
August 22, 2016

maths
If there are x liters of 25/L then we have the value of the milk as 25x + 30(60-x) = 1600
August 22, 2016

math
distance = speed * time, so (1/2 hr) * (y mi/hr) = y/2 mi
August 22, 2016

Math
4/(5+4+y)
August 22, 2016

phy
the waves are a sin(x) and b sin(x-k) add them up and you have a sinx + b(sinx cosk - cosx sink) = (a+b*cosk)sinx - (b*sink)cosx This is basically just Asinx + Bcosx which can be reduced to a single sine wave of amplitude √(A^2+B^2) See a nice discussion at https://en....
August 22, 2016

pre caluclus
since you give only one focus, I assume it's a parabola. Since both points lie on the line y=2, the parabola opens horizontally. Recall that y^2 = 4px has focus at (p,0) and vertex at (0,0) Your parabola has obviously been shifted up by 2, so it will be (y-2)^2 = 4px Your ...
August 22, 2016

Math
just recall that supplementary angles add to 180, so 4x+3 + 3x-5 = 180 Now just solve that for x.
August 22, 2016

Algebra 1
the first step is usually to clear all the fractions by using the LCD. In this case 12. Do that and you have z/3 - 3 = z/4 + 7 4z - 36 = 3z + 84 z = 120 Or, you can collect terms as usual, and then clear fractions z/3 - 3 = z/4 + 7 z/3 - z/4 = 10 (1/3 - 1/4)z = 10 1/12 z = 10 ...
August 22, 2016

algebra
These are all difference of squares or sum/difference of cubes. You need to be able to recognize such values, and apply the formulas: a^2-b^2 = (a-b)(a+b) a^3±b^3 = (a±b)(a^2∓ab+b^2) For example, 16x^4a-y^8a = a(16x^4-y^8) = a(4x^2+y^4)(4x^2-y^4) = a(4x^2+y...
August 22, 2016

Algebra
since V is proportional to r^3, V(2r)/V(r) = 2^3 gather all the constants into a single k, and you have V(r) = kr^3 V(2r) = k(2r)^3 = k(2^3)(r^3) = 2^3*V(r)
August 22, 2016

math
one every polynomial of degree n has exactly n solutions.
August 22, 2016

Algebra 1a
no kidding. In big letters on the home screen it says Post homework questions online a general whine is not a homework problem.
August 22, 2016

Math
2450 - 2549 but I must say I do not care for the way the question was worded.
August 22, 2016

Algebra
√(3x-6) = 4 3x-6 = 4^2 = 16 3x = 22 x = 22/3
August 22, 2016

Algebra
3c^2 - 5c - 7.8 = -2.2 3c^2 - 5c - 5.6 = 0 Now just use the quadratic formula
August 22, 2016

Math
correct
August 22, 2016

Algebra
well, you know that y = 3.8x+2.2 so use that in the other equation to get 4.5x - 6.7(3.8x+2.2) = 8.6 4.6x - 25.46x - 14.74 = 8.6 now it's easy, right? Then, once you have x, use that to get y.
August 22, 2016

Math
1st step: subtract 5.514 from both sides: 9.2x = 152.72 I guess you can figure out what's next, no?
August 22, 2016

Algebra
65.9 - 32.4k/9.9 = 13.3k 65.9 - 3.28k = 13.3k Think you can handle that now?
August 22, 2016

Absolute Value
all correct.
August 22, 2016

Algebra
why all the words? You showed the math. Just solve the way you normally would; don''t let the fractions confuse things. 1/2.75 = 1/3.2 - 1/x 1/x = 1/3.2 - 1/2.75 1/x = (2.75-3.2)/(3.2*2.75) x = (3.2*2.75)/(2.75-3.2) = 8.8/-0.45 = -19.556 Or, just convert to decimals at...
August 22, 2016

math
sheet area: 32*24 buttons area: 64 * π * 3.5^2 now just subtract
August 22, 2016

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