Saturday

November 28, 2015
Total # Posts: 31,850

**Business Math**

interest due at the end of 120 days = 8500(120/365)(.09) = 251.51 so of his $4000 payment, $3748.49 will go towards reducing the debt. so balance owing = 8500 - 3748.49 = 4751.51 interest for the remaining 80 days = 4751.51(.09)(80/365) =93.73 total owing at the end = 4751.51+...
*November 19, 2015*

**MATH**

I will assume that #1 is 12/x = -3 multiply both sides by x --> 12 = -3x divide both sides by -3 -4 = x or by the "just look at it theorem" ... What must 12 be divided by to get an answer of -3 ?? #2 24 = 120/x do the same thing as in #1 24x = 120 x = 120/24 = 5
*November 19, 2015*

**Rudy - Truda :Algebra 2**

Please use the same nickname throughout your different posts. You are making things way too complicated. You are looking at a difference of squares x^6 - 64 = (x^3 -8)(x^3 + 8) now I see a sum and a difference of cubes = (x-2)(x^2 + 2x + 4)(x+2)(x^2 -2x + 4) the two quadratics...
*November 19, 2015*

**Algebra 2**

Bob, in line #2 , you forgot to divide the 1 by 3 it actually factors into (x+1)(3x-1) = 0 so x = -1 or x = 1/3
*November 19, 2015*

**Calc**

I am sure you meant to say: 2(2)^(t/10) other than that, you are correct
*November 19, 2015*

**Geometry**

The volume of the cylinder does not enter into the problem. As Bob pointed out, the dropped sphere will simply displace its own volume, which is (4/3)π(2^3) = 32π/3 cm^3 The sphere could have been dropped in any container, a fruit bowl, a coffee can, or whatever as ...
*November 19, 2015*

**algebra**

easiest way: multiply each term by 60 , the LCD 15x - 12x - 20 = 64 take over
*November 19, 2015*

**algebra**

enlarge it just once with a scale factor of 8
*November 19, 2015*

**Algebra 1**

If you have two lines with different slopes and different y-intercepts, they MUST intersect and you will ALWAYS have a solution
*November 19, 2015*

**Geometry**

(x,y,z) ---->(3x,3y,3z) so (-1,-2,0) ---> .......
*November 19, 2015*

**math**

each side is √256 or 16 so the perimeter is 64 you were right the first time
*November 19, 2015*

**algebra**

The coefficient of 3x^2 is 3. The exponent is 2
*November 19, 2015*

**Pre-Calc**

I am having the same problem Steve had, when this same question was posted 2 years ago http://www.jiskha.com/display.cgi?id=1382575312 Notice , the wording is identical, just the angles have been changed.
*November 19, 2015*

**math**

purchase cost = 10(22) = 220 number of eggs bought = 120 number rotten = 6 good eggs = 114 return = 114(2.5) = 285 profit = 285-220 = 65 you were correct
*November 19, 2015*

**Algebra(please check my answers)**

correct again
*November 19, 2015*

**math**

let each of her halves be x .06x + .10x = 680 .16x = 680 x = 4250 so she invested twice that or 8500
*November 19, 2015*

**Calculus**

the way I read that is that you first want to divide x by 6x-5, and then integrate that series using long division .... x/(6x-5) = 1/6 + 5/(36x) + 25/(216x^2) + 125/(1296x^3 + .. (a geometric series with a = 1/6 and r = 5/(6x) so ∫x/(6x-5) dx = ∫(1/6 + 5/(36x) + 25...
*November 19, 2015*

**Math/ algebra please help**

Y - 5=1 over 3 ---> y-5 = 1/3 ?? of so, then y = 5 1/3 = 16/3 not one of the choices if you meant: (y-5)/3 = 1, which you did not say, then y-5 = 3 y = 8 , which would be choice B. Since you did not state your choices, ......
*November 19, 2015*

**Math**

You should have a 3D diagram. let the distance on the ground be x x^2 = 80^2 + 60^2 let the distance from start to finish be y y^2 = x^2 + 30^2 = 80^2 + 60^2 + 30^2 10900 y = √10900 = 104.4 m or, using vectors distance vector = (0,80,0) + (60,0,0) + (0,0,30) = )60,80,30...
*November 19, 2015*

**Delhi International Happy School**

it also said, what fraction of her balloons was not yellow? 10 were not yellow ---> 10/12 = 5/6
*November 19, 2015*

**Algebra I**

looks good to me
*November 19, 2015*

**math miss.sue can u plz check me answers plz**

the correct answer is d
*November 19, 2015*

**Math**

Easy to lose count with all those zeros I do them this way (4 x 10^9)(6 x 10^6) = (4x6)(10^9 x 10^6) = 24 x 10^15 = 2.4 x 10^16 (5 x 10^7)(3.6 x 10^3) = 18 x 10^10 = 1.8 x 10^11 YOu were right with your corrected post
*November 19, 2015*

**math**

volume if full = 5^3 = ... but 1/5 is empty, so ?? is filled with water water = ?? * 5^3 = ....
*November 19, 2015*

**Math PLEASE HELP NOW**

To be able to handle these types of exponent questions, you must have been given the basic laws of exponents, or they will be found in your text or notes. your first question matches the rule that (a^x)^y = a^(xy) so , (x^3)^5 = x^15 #2 is the same #3, you will need a^x / a^y...
*November 19, 2015*

**A.AA.SK.v. math**

A poorly communicated question. I would guess that you have an arithmetic sequence of 2, 7, 12, ... and you want the 10th term. a =2, d=5 term(n) = a + (n-1)d term(10) = 2 + 9(5) = 47
*November 19, 2015*

**math**

SA of original cube = 6(4^2) = 96 cm^2 I will assume it will be cut into cubes, each one i cm on a side. So number of such cubes = 4^3 / i^3 surface area of each small cube = 6i^2 total surface area of all the little cubes = (4^3)/(i^3)*(6i^2) = 64(6)/i = 384/i so ratio of SA ...
*November 19, 2015*

**Math**

did this for you yesterday http://www.jiskha.com/display.cgi?id=1447865841
*November 19, 2015*

**Math**

profit = revenue - expenses P(x) = x(100-10x) - (5x^2 - 800x + 500) = 900x - 15x^2 - 500 P ' (x) = 900 - 30x = 0 for a max of P 30x=900 x=30 P(30) = 13000
*November 19, 2015*

**math**

simplest way i can see: purchase price = 400 at 8.40 or 100 at 2.10 profit of 15% of 2.10 = 1.15(2.10) = 2.415
*November 18, 2015*

**Math**

i = .08/4 = .02 n = 3(4) = 12 paym = ? amount = 1,000,000 paym( 1.02^12 - 1)/.02 = 1,000,000 paym = ......
*November 18, 2015*

**geometry**

-n+6=8n+6n 6 = 15n n = 6/15 = 3/5 ≠ 0 do you have a typo ??
*November 18, 2015*

**correction - Maths**

So if she spent 40% of her money, she had 60% of her money left, which is 120 so .6x = 120 x = 120/.6 = 200 check: 40% of 200 = 80 leaving her with 120 Marie you took 40% of what she had left.
*November 18, 2015*

**math**

π/3 radians corresponds with 60° You should memorize the sides of the 30-60-90° triangle as 1 , √3, 2 so sin π/3 = √3/2 and tan π/3 = √3/1 = √3 now add them up
*November 18, 2015*

**math**

let the unit digit be y let the tens digit by x the original number is 10x + y the number reversed is 10y + x 10y + x = 10x + y - 36 9y - 9x = -36 x - y = 4 10x+y - (10y+x) = 36 9x - 9y = 36 ----> x - y = 4 x = 4+y x+y = 2.5(x-y) 2x + 2y = 5(x-y) 2x + 2y = 5x - 5y 7y = 3x (...
*November 18, 2015*

**Math**

43/30 hrs = 1 13/30 hr = 1 hour and 26 minutes
*November 17, 2015*

**Math**

Anna's present age -- x Jun's present age ---- y in 5 yrs form now: Anna --- x+5 Jun ----- y+5 x+5 = 2(y+5) x+5 = 2y + 10 x - 2y = 5 5 years ago: Anna --- x-5 jun ----- y-5 x-5 = 3(y-5) x-5 = 3y - 15 x - 3y = -10 subtract the two equations: y = 15 then in x - 2y=5 x - ...
*November 17, 2015*

**MATH**

all are correct
*November 17, 2015*

**Pre calc**

both u and v are in quadrant III from sin u = -8/17 ----> y = -8 , r = 17 x^2 + 64 = 289 --> x = -15 in quad III cosu = -15/17 from cos v = 12/13 ---> x = 12, r = 13 y = ± 5 if v is in I, sinv = 5/13 , cosv = 12/13 if v in in IV , sinv = -5/13, cosv = 12/13 cos...
*November 17, 2015*

**math**

number of rolls with evens = 10 + 3 + 2 = 15 so .....
*November 17, 2015*

**math**

present ratio of white :striped = 16:8 = 2:1 white added = x striped added = 132-x (16 + x)/(8 + 132-x) = 2/1 16+x = 16 + 264 - 2x 3x = 264 x = 88 he should add 8 whites and 44 whites check: new whites = 16+88 = 104 new stripes = 8+44 = 52 104:52 = 2:1
*November 17, 2015*

**Catholic university of Cameroon bamenda**

100x-500y-5x^2-5y^2=0 or 5y^2 + 500y - 100x+5x^2 = 0 y^2 + 100y - 20x+x^2 consider this to be a quadratic equation with variable y, so that a = 1 b= 100 c = (x^2 - 20x) then y = (-100 ± √(100^2 - 4(1)(x^2 - 20x) ) ) /2 = (-100 ± √10000-4x^2 + 80x)/2...
*November 17, 2015*

**Polynomial**

last one should be 4. sneaky one ... 9x^4-37x^2+4 = (9x^2 - 1)(x^2 - 4) = ..... can you finish it ?
*November 17, 2015*

**Polynomial**

1. take out common factor of x, the rest factors 2. factor out x^2, then difference of squares. one of them goes again. 3. x^3 + 3x^2 - 16x - 48 looks like "grouping" works here = x^2(x+3) - 16(x+3) = (x+3)(x^2- 16) , and a difference of squares =(x+3)(x+4)(x-4) 4. ...
*November 17, 2015*

**college readiness**

let one number be x let the other be 5x x + 5x = 312 carry on
*November 17, 2015*

**math**

width of base = 28-16 = 12 m length of base = 36-16 = 20 m height of box = 8 m volume = 12(20)(8) = 1920 m^3 (why introduce variables when there is no need for them ?)
*November 17, 2015*

**Algebra**

You clearly must have a calculator that is programmed to do scatter plots and curves of best fit. I don't have one.
*November 17, 2015*

**math**

you want height to be zero, so 0 = 96+80t -4.9t^2 using the formula ... t = (-80 ± √8281.6)/-9.8 = appr 17.45 seconds or a negative
*November 17, 2015*

**Math**

width --- x length ----x+60 x(x+60) = 16000 x^2 + 60x = 16000 completing the square is easy here x^2 + 60x + 900 = 900+16000 (x+30)^2 = 16900 take √ x+30 = 130 x = 100 width is 100 ft, length is 160 ft
*November 17, 2015*

**Mathematics**

We don't know the intersection of all three circles, so label it x Now go to the intersection of two of the circles, say, the M and B circles It says that sum is 15, but we have already counted x of them, so in the remaining part of the football-shaped region is 15-x Do ...
*November 17, 2015*

**maths**

volume of the original spheres = (4/3)π (1^3 + (3/2)^3 + 2^3) = (4/3)(99/8)π or 16.5π radius of big sphere ---> r cm (4/3)π r^3 = (4/3)(99/8) π r^3 = 99/8 r = 99^(1/3)/2 or the cuberoot of 99 /2 diameter = 2r = cuberoot(99) = appr 4.626 cm
*November 17, 2015*

**math**

or let the two numbers be 4x and 7x 7x - 4x = 48 3x=48 x = 16 so the two numbers are 4(16) or 64 and 7(16) or 112
*November 17, 2015*

**Algebra 2**

well, aren't the intercepts points ? e.g. x-intercept = 6 ----> you have a point (6,0) y-intercept = -8 ---> your second point is (0,-8) can you handle it now?
*November 16, 2015*

**Calc**

let each cut-out have sides of x inches each length of box = 16-2x width of box = 10-2x , where x < 5 height of box = x volume = V = x(16-2x)(10-2x) expand, take derivative, set derivative, which is a quadratic, equal to zero and solve. Make sure you take the value between ...
*November 16, 2015*

**Calc**

area = π r^2 d(area)/dt = 2π r dr/dt given: dr/dt = 2.6 , r = 4 d(area)/dt = ..... just plug in your values. Mind the units
*November 16, 2015*

**Math**

let length of printed area be x let the width be y so xy = 384 y = 384/x length of paper = x+12 width of paper = y+14 area of paper = (x+12)(y+14) = xy + 14x + 12y + 168 = x(384/x) + 14x + 14(384/x) + 168 = 384 + 14x + 5376/x + 168 d(area)/dx = 14 - 5376/x^2 = 0 for min of ...
*November 16, 2015*

**Trig**

first path: 4 hrs at 20 knots = 80 n miles second path: 6 hrs at 20 knots = 120 n miles angle between them = 90+47 = 137° I see a clear case of the cosine law: let x be the distance from port x^2 = 80^2 + 120^2 - 2(80)(120)cos137 = .... x = √.... you do the button-...
*November 16, 2015*

**business algebra**

1 1 -1 0 1 2 4 -3 3 -1 -22 19 1 1 -1 0 0 1 5 -3 --- I did #2 - #1 0 -4 -19 19 -- I took #3 - 4x#2 1 1 -1 0 0 1 5 -3 0 0 1 7 --- I took #3 - 3x#2 so z = 7 in #2: y + 35 = -3 y = -38 in #1 x - 38 - 7 = 0 x = 45 x=45 , y=-38 , z=7
*November 16, 2015*

**correction - math trigonometry**

just realized I made an arithmetic error in finding angle APB angle APB = 11° , not 53 so please make the necessary changes. by the sine law: BP/sin21 = 100/sin11 BP = 100sin21/sin11 = .... you do that, store answer in calculator's memory the rest stays the same
*November 16, 2015*

**math trigonometry**

make your sketch, and label the top of the building P and the bottom of the building R In triangle ABP, angle A = 21° angle ABP = 148° so angle APB = 53° by the sine law: BP/sin21 = 100/sin53 BP = 100sin21/sin53 = .... you do that, store answer in calculator's ...
*November 16, 2015*

**Math**

your presentation of 3.75+3.75+2+2=11.5. 11.5*.5= 5.75. 5.75*$20=115 would not be acceptable to me. besides, it makes no sense. original length = 3.75 m original width = 2 m new length = (3.75 + 1) m = 4.75 m new width = (2 + 1) m = 3 m area including border = 4.75 x 3 m^2 = ...
*November 16, 2015*

**Math**

appr 20% of 300 which is 60
*November 16, 2015*

**math**

distance covered in 1 rotation = 10π inches distance covered in 200 rotations = 2000π inches speed = 2000π inches per 1 minute you did not specify which units your answer should be in.
*November 16, 2015*

**math**

let total spectators be x 1/4 of them are men , leaving 3/4 x women and children (2/5)(3/4)x = 132 (3/10)x = 132 3x = 1320 x = 440 so 1/4 of 440 are men = 110 women = 132 so far we have 242 leaving 440-242 or 198 children check: total = 440 men = (2/5)(44) = 110 leaving 330 ...
*November 16, 2015*

**Precalc**

sum of 15000 + 15000(1.03) + 15000(1.03^2 + ... for 7 terms sum = a(r^2 - 1)/(r-1) = 15000( 1.03^7 - 1)/(1.03-1) = 114,936.93
*November 16, 2015*

**Math**

24, 5, 16 7, 15, 23 14, 25, 6 Each row and each column adds up to 45 Not only that, but each diagonal also adds up to 45
*November 16, 2015*

**Pre-Calculus**

looks like an arithmetic sequence with terms: 3, 7, 11, .... a = 3, d=4 , n = ? so that term(n) ≥ 115 term(n) = a + (n-1)d 6 + 4(n-1) ≥ 115 4n - 4 ≥ 109 4n ≥ 113 n ≥ 28.25 on day 28 he will do 6 + 4(27) or 114 push-ups so he will need 29 days to ...
*November 16, 2015*

**Algebra**

clearly A just let n = 1, 2, 3, ... to get the scores listed your choice, on the second play where n = 2, would produce a score of 4453(2) + 73 or 8979
*November 16, 2015*

**Algebra 2**

-16t^2 + 500 = 0 16t^2 = 500 t^2 = 500/16 = 31.25 t = √31.25 = appr 5.59 seconds
*November 16, 2015*

**maths**

1. I will assume that by "swapped" you mean the same number so (2/5)x = 9 2x = 45 x = not a whole number, so my assumption is wrong Not enough information 2. so he sold them for 10(1.90) = 19.00 This includes a profit of 8.00 so the purchase price was 11.00 for the ...
*November 16, 2015*

**Trig**

take the messy part ... csc^-1 (x/(x-1) ) represents an angle Ø so that csc Ø = x/(x-1) or sinØ = (x-1)/x so make a sketch of a right-angled triangle with hypotenuse x and opposite side x-1 call the adjacent side b then b^2 + (x-1)^2 = x^2 b^2 + x^2 - 2x...
*November 16, 2015*

**algebra**

Since it is parallel, the new equation must look like y = -x + b, (it would differ only in the constant) but (2,-2) lies on this line, so -2 = -(2) + b b = 0 new equation : y = -x
*November 16, 2015*

**math**

the LCD is 105 so multiply each part by 105 4/5 ≥ 2/3 - 2/7x 84 ≥ 70 - 30x 30x ≥ 70 - 84 30x ≥ -14 x ≥ -14/30 x ≥ -7/15
*November 16, 2015*

**trigonometry**

Trust yourself. cosØ = adjacent/hypotenuse cos 50° = x/350 350(cos50) = x x = appr 224.98 clearly the answer key is wrong.
*November 16, 2015*

**trigonometry**

Did you make a sketch to see that cos 50° = x/350 ? solve for x
*November 16, 2015*

**algebra help!**

Why are you guessing? This is Math. btw, you "guessed" incorrectly, you took 65% of 26 the 26 represents the 65% of the total students who happen to eat pizza. let the number of students be x 65% of x = 26 .65x = 26 x = 26/.65 = 40 check: what is 65% of 40 ?
*November 16, 2015*

**Math 116**

let the weight of the brick be x lbs x = (1/2)x + 3/4 times 4 4x = 2x + 3 carry on
*November 16, 2015*

**Math**

You followed my steps only up to a point combined rate = 9/60 ---- correct time at combined rate = 1/(9/60) = 1 ÷ (9/60) = 1 (60/9) = 60/9 = 15 minutes You just divided 9 by 60 to get .15 and it is just coincidence that the digits of .15 and the correct answer of 15 are...
*November 16, 2015*

**Math**

use the same method I just showed you in your previous post. Let me know what you got.
*November 16, 2015*

**Math**

Peter's rate = 1/5 rooms/hour Juan's rate = 1/3.75 rooms/hr = 100/375 = 4/15 combined rate = 1/5 + 4/15 = 7/15 time at combined rate = 1/(7/15) hrs = 15/7 hrs = aprr 2.14 hrs, or 2 hrs and 9 minutes
*November 16, 2015*

**math**

panels produced by plant A --- x panels produced by plant B = x+8000 defective from A = .04x defective from B = .03(x+8000) solve for x: .04x + .03(x+8000) = 660 (I would get that "caps lock" key fixed on your device)
*November 16, 2015*

**Math**

volume of old = π r^2 h = π(36)(12)= 432π this must stay the same we know the new h, but not the r new volume = 3π r^2 so 2π r^2 = 432π divide by 2π r^2 = 216 r =√216 = appr 14.7 SA = 2πr^2 + 2πrh old SA = 2π(36) + 2π...
*November 16, 2015*

**algebra**

you could say that the increase is somewhat linear, (straight-lined), and let the equation be cost = .59n + .15, where n is a multiple of 10 with 1960 represented by n=0 so 2020 would be n = 6 (2020 = 1960 + 60 and 60 = 6(10) ) cost = .59(6) + .15 = 3.69
*November 16, 2015*

**math**

two step process 1. move all terms except the y term to the other side 3y = -4x + 12 2. divide each term by the coefficient of the y term y = (-4/3)x + 4 use the properties of y = mx + b to answer b) and c)
*November 15, 2015*

**statistics**

z-score for you time of 90 minutes = (90-79)/8 = 1.375 from tables or from my favourite webpage probability not finishing = .0846 so of 60 students not finishing = .0846(60) = 5.076 so 5 students will not finish http://davidmlane.com/hyperstat/z_table.html
*November 15, 2015*

**math**

sub in the values: [ (-2)^-1 (3) + 3^-1 ]^(-2(-1)) = [ 3(-1/2) + 1/3) ]^2 = [ -3/2 + 1/3]^ = [ -1/3 ]^2 = 1/9
*November 15, 2015*

**Math**

1. correct 2. p/6 = 7/8 ---> p= 42/8 = 5.25 3. correct 4. 521 miles in 14 hrs = 521/14 mph = 37.21 mph Your answer should have hit you as totally unreasonable. 5. 33.6 gallons in six months --> 33.6/6 gal/mon = 5.6 gallons/month 6. .81 euro = 1 dollar 1 eur = 1/.81 ...
*November 15, 2015*

**Maths**

First part is correct. not familiar with B) part of your question.
*November 15, 2015*

**math**

let y = x^2 - 4 and sketch it here is a picture, using that sketch you should be able to answer all questions http://www.wolframalpha.com/input/?i=plot+y+%3D+x%5E2+-+4 e.g. "Intervals on which the graph is below the x axis " ----> -2 < x < 2
*November 15, 2015*

**Quantitative Analysis**

I have no idea what these numbers are supposed to be. If you are finding the z-score, your mathematical form is really bad z-score for 11.33 = (11.33-8.27)/1.53 = 2 I you are using tables, a z-score of 2 has value of .9772 that is 97.72% will have a shoe size below 11.33 which...
*November 15, 2015*

**Math**

first rate = 225/5 words per minute = 45 words/min 2nd rate = 135/3 words per min = 45 words/min ahhh, the same rate so words typed = 24(45) or 1080 words
*November 15, 2015*

**Math**

7x-5=4x+4 7x - 4x = 4+5 3x = 9 x = 3
*November 15, 2015*

**algebra**

if you meant: f(x) = √x + 5, the domain is any real number, x ≥ 0 if you meant: f(x) = √(x+5) , the domain is any real number x ≥ = -5
*November 15, 2015*

**math**

correct
*November 15, 2015*

**Math**

3 3/7 = 24/7 so the reciprocal is 7/24
*November 15, 2015*

**Trigonmetry**

I assume we are solving .... 4√(1- sin^2 2x) ) + 3sin 2x = 2 √(1-sin^2 2x) = (2 - 3sin 2x) /4 square both sides 1 - sin^2 2x = (4 - 12sin 2x + 9sin^2 2x)/16 let sin 2x = y, so we have 1 - y^2 = (4 - 12y + 9y^2)/16 16 - 16y^2 = 4 - 12y + 9y^2 25y^2 - 12y - 12 = 0 y...
*November 15, 2015*

**Calculus 1**

Just did this for you. Look back to your earlier post of this
*November 13, 2015*

**TayB's question - Calculus 1**

let the point of contact be (a,b), then b = (a-5)^2 = a^2 - 10a + 25 sketch the tangent and the normal y' = 2(x-5) = 2x - 10 so the slope of the tangent at (a,b) = 2a - 10 and the slope of the NORMAL at (a,b) = -1/(2a - 10) or 1/(10-2a) but using the old grade 9 way of ...
*November 13, 2015*

**Calculus 1**

let the equation of the tangent be y = mx, where m is the slope Here is a picture with m = 1/2 http://www.wolframalpha.com/input/?i=plot+y+%3D+-4sinx+%2C+y+%3D+.5x+%2C++from+0+to+20 Here is a picture with m = .9 http://www.wolframalpha.com/input/?i=plot+y+%3D+-4sinx+%2C+y+%3D...
*November 13, 2015*

**algebra**

how about 5n + 10d ≤ 50 n + 2d ≤ 10 , where n and d are whole numbers
*November 13, 2015*