Saturday

August 29, 2015
Total # Posts: 30,673

**maths**

I did this last Wednesday http://www.jiskha.com/display.cgi?id=1424295544
*February 21, 2015*

**Math**

Clearly, since 3 does not divide evenly into 25, you cannot do this without some marbles left over.
*February 21, 2015*

**Math**

∛64 = 64^(1/3) = 4 = 2^2 243^1/5 = 3 so 6 log2 ∛64 +10log3 (243)^1/5) = 6log2 (2^2) + 10 log3 (3) = 6(2 log2 2) + 10 log3 3 = 12 (1) + 10(1) = 22
*February 21, 2015*

**Math**

I like Steve's thinking, but sometimes I like to take a hammer to a thumbtack.
*February 21, 2015*

**Math**

Yes, you are adding 5+10+15+...+45+50 here a=5 and d = 5 How many terms are there? term(n) = a+(n-1)d 50 = 5 + (n-1)(5) 45 = 5n - 5 50 = 5n n = 10 so we want the sum of 10 terms sum = (10/2)(first + last) = 5(5+ 50) = 275
*February 21, 2015*

**math**

Meg's age --- x Jill's age ----- x-2 Beth's age --- x/2 or (1/2)x Of course we could have started by defining: Beth's age --- y Meg's age --- 2y Jill's age -----2y - 2 or , starting with Jill's age ----- z Meg's age ---- z+2 Beth's age...
*February 21, 2015*

**math**

If we consider 2004 to be represented by 0, then 2009 would correspond with 5 and we have two ordered pairs (0,14.54) and (5,15.37) slope = (15.37-14.54)/(5-0) = .83 N = .83t + c at (0,14.54) 14.54 = 0 + c , c = 14.54 N = .83t + 14.54 , where t is in years since 2004 and N is ...
*February 20, 2015*

**correction _ Last help Thanks**

Argghhh! the odds AGAINST drawing an S = 7 : 3
*February 20, 2015*

**Last help Thanks**

prob of drawing an S = 4/11 prob of NOT drawing an S = 1 - 4/11 = 7/11 So the odds in favour of drawing an S = (4/11) : (7/11) = 4 : 7 So the odds AGAINST drawing an S = 3 : 7 I would say, "Karen, read the question carefully"
*February 20, 2015*

**help please**

odds in favour of some event = probability of that event happening : probability of the event NOT happening so if the odds of something happening is 3: 4 then the probability of the event happening is 3/7 in general if the odds of something is a : b then prob of that something...
*February 20, 2015*

**math**

total amount invested ---- x Fatuma's share = x/4 Ali's share = (2/5)(3x/4) = 3x/10 Hassan's share = (3/2)(x/4) = 3x/8 so far they have: x/4 + 3x/10 + 3x/8 = 10x/40 + 9x/40 + 15x/40 = 37x/40 so they are still short 3x/40 3x/40 < 3x/8 by 60000 3x/40 = 3x/8 - ...
*February 20, 2015*

**math**

sinØ= 2/3 , Ø is in quad I in my triangle, x = ? , y = 2, r = 3 x^2 + 2^2 = 3^2 x^2 = 5 x = √5 tanØ = y/x = 2/√5 or, if rationalized, 2√5 /5
*February 20, 2015*

**Math**

5 gifts take 1.5 rollos 1 gift takes 1.5/5 rolls 9 gifts take 9(1.5/5) rolls or 2.7 rolls or 9/5 = x/1.5 x = 1.5(9/5) = 2.7
*February 20, 2015*

**Algebra**

let the side parallel to the house be y ft let each of the other two sides by x ft so 2x + y = 164 y = 164 - 2x area = xy = x(164 - 2x = -2x^2 + 164x This is a downwards opening parabola, so we need its vertex. Either 1. complete the square 2. use Calculus 3. use " the x ...
*February 20, 2015*

**math.help pls**

all you have to look at is B(5,-6,-1) If you are using the standard position of x-axis towards and away from you, the y-axis left and right, and the z-axis up and down, then B ---> 2 units back, 3 units right, and 1 unit up ---> B' (3, -3, 0) , then B'(3,-3,0...
*February 20, 2015*

**Math Help**

3u ∙ v = <6,6> ∙ <-3,4> = -18 + 24 = 6 (u ∙ 2v)w = ( <2,2> ∙ <-6,8>)<1,-2> = (-12 + 16)<1,-2> = 4<1,-2>= <4,-8>
*February 20, 2015*

**Math**

i = .035/365 = .00009589.. (I store this in my calculator memory so I don't lose any accuracy) amount = 28000(1 + .00009589..)^68 = 28183.16 for the 2nd problem, the 3000 earns interest for 20 + 30 or 50 days the 650 for 10+30 or 40 days then 1200 for 12 days amount = 3000...
*February 20, 2015*

**Math**

1. dot product u ∙ v = |u| |v| cosØ, where Ø is the angle between them, so <2,-3> ∙ <1,-2> = √13 √5 cosØ 2+6 = √13√5cosØ cosØ = 8/(√13√5) = .99227... Ø = appr 7.1° do #2 ...
*February 20, 2015*

**Maths**

Of course not. It only increases by 3 for this question since this arithmetic series has a common difference of 3 It depends totally on the sequence
*February 20, 2015*

**Maths**

Nothing very exciting. It just blows up, getting bigger and bigger You are just adding 3 to each new term added.
*February 20, 2015*

**Math**

in general: <a, b> ∙ <c, d> = ac + bd so <0, 3> ∙ <4, -2> = 0 + (-6) = -6 repeat for #2
*February 20, 2015*

**math**

either 2 men or 2 women. with no restriction: number of choices = C(5,2) = 10 number choices of 2 women = C(2,2) = 1 number of choices of 2 men = C(3,2) = 3 prob of 2 of same sex = 4/10 = 2/5 prob of 2 of opposite sex = 1 - 2/5 = 3/5
*February 20, 2015*

**math**

L1: y-2 = 5(x-1) y-2 = 5x-5 5x - y = 3 L2: x + 5y = c from L1, when x = 4, y = 17 so (4,17) into L2 4 + 85 = c = 89 L2: x + 5y = 89 or y = (-1/5)x + 89/5
*February 20, 2015*

**trignometry**

Iwill read that as 1/(1 - cscx) - 1/(1 + cscx) = -2tanx secx LS = (1 + cscx - (1 - cscx))/(1 - csc^2 x) = 2cscx/(-cot^2 x) = -2 (1/sinx)(tan^2 x) = -2(1/sinx)(sin^2 x/cos^2 x) = -2 cscx/cos^2 x = -2 cscx sec^2 x = RS
*February 20, 2015*

**math**

90/x = 5^2/10^2 90/x = 25/100 = 1/4 x = 360
*February 20, 2015*

**math**

follow the same method I showed you in your other post with a similar concept Except here you have areas instead of volumes Hint: areas of similar shapes area proportional to the square of their corresponding sides.
*February 20, 2015*

**Math**

prob of grey = 87/100 number of greys in 220 = (87/100)(220) = appr 191
*February 20, 2015*

**Math**

number = (1/50)(750) = 15
*February 20, 2015*

**maths**

visualize the box cut open and laid out flat on a table. What do you see ? Calculate the area of each of the 5 rectangles and add them up
*February 20, 2015*

**Math**

prob of 4 spades = C(13,4)/C(52,4) = 715/270725 = 11/4165
*February 19, 2015*

**Math**

original square is x by x cm new rectangle is x by x/2 2( x + x/2) = 24.9 2x + x = 24.9 x = 8.3 the square piece is 8.3 by 8.3 cm
*February 19, 2015*

**Math**

volume of similar solids is proportional to the cube of their corresponding sides 240/x = 92^3/23^3 240/x = 778688/12167 778688x = 12167(240) x = 3.75 or 3.8 to the nearest tenth
*February 19, 2015*

**Math (Probability)**

You want the 8 of hearts, then an Ace prob = (1/52)(4/51) = 1/663
*February 19, 2015*

**Algebra 2**

t3 = ar^2 = -75 t6 = ar^5 = -9375 divide them r^3 = 125 r = 5 in ar^2 = -75 a(25) = -75 a = -3 term(n) = -3(5)^(n-1)
*February 19, 2015*

**Math**

I assume the median is 87 z-score = (91-87)/4.01 = ....
*February 19, 2015*

**math**

You are basically going through the development of the formula, using a specific example You seem to have a typo your: 3²+3³+3to the power of 6+...to 20 terms makes little sense I will assume we have S(20) = 3^2 + 3^3 + ... + 3^21 multiply both sides by 3 3S(20) = 3^...
*February 19, 2015*

**MATH**

Typo: you have Sn=n/2[a+1] clearly should be : Sn=n/2[a+l] let S(n) = a + (a+d) + (a+2d) + ... +(l-2d) + (l-d) + l , for n terms we could just write this turned around S(n) = l + (l-d) + (l-2d) + ... + (a+2d) + (a+d) + a add these two equations 2S(n) = a+l + (a+d+l-d...
*February 19, 2015*

**MATH**

I will assume that you are adding the corresponding terms of each sequence, that is .. new sequence: t1 = a+a t2 = a+d + ar t3 = a+2d + ar^2 etc so a+a = 4 a+d + ar = 20 but d=-2 and r=3 2a = 4 a = 2 So all is known t3 = 2 - 4 + 2(9) = 16 check: AS: 2, 0, -2, -4, .. GS: 2, 6, ...
*February 19, 2015*

**math**

Use the formulas for both "sum of terms" and "sum of infinite number of terms" Sum to infinity = a/(1-r) a/(1-r) = 243 , ---- #1 ( I recognized 243 as 3^5) a = 243 - 243r sum(5) = a(1 - r^5)/(1-r) 242 = a(1 - r^5)/(1-r) ---- #2 divide #2 by #1 1-r^5 = 242/...
*February 19, 2015*

**Algebra 2**

∑ 2n/(n+4) , where n = 1 to 5 write n=1 underneath the sigma symbol and 5 above it
*February 18, 2015*

**Math Help Please**

You must mean: (4x^3 + 5x^2 - 12x + 27)/(x + 3) I did a synthetic division and got 4x^2 - 7x + 9 , which is A since none of the answers had a remainder, you knew the division had to be exact, so it had to look like this (4x^3 + 5x^2 - 12x + 27) = (x+3)(4x^2 .... +9) so it had ...
*February 18, 2015*

**math**

going to the theatre C = 12.5n, where n is the number of movies seen buying a player, then renting C = 125 + 1.95n 12.5n = 125 + 1.95n 10.55n = 125 n = 11.8 I will let you interpret that decimal answer
*February 18, 2015*

**algebra**

let the side parallel to the barn be y yards then the other two sides are x yards each 2x + y = 25 y = 25-2x area = xy = x(25-2x) = 25x - 2x^2 which graphs as a downwards parabola, so the vertex has to be found. quickest way: the x of the vertex is -b/(2a) = -25/-4 = 6.25 then...
*February 18, 2015*

**ALGEBRA**

unless [ ] is defined as something special, f(2) = 2*(-1)^2 = 2*(1) = 2
*February 18, 2015*

**math**

reflection of P(-3,5) in the x-axis ----> R(-3,-5) which is in quadrant III P(-3,5) reflected in the y-axis---> S(3,5) , which is in quad I
*February 18, 2015*

**Jonie, Pamela, Spartans - math**

Why are you changing names, and what could you not understand about my answer here: http://www.jiskha.com/display.cgi?id=1424281591
*February 18, 2015*

**Math**

the resultant vector is (9-1 , 3-11) = (8,-8) This is generally considered in component form check with your textbook how they write the vector. Some authors avoid the standard round brackets ( ..., ...) to avoid confusion with a point. Some use this form [8,-8] others use <...
*February 18, 2015*

**Calculus**

not an easy problem follow these steps: http://mathworld.wolfram.com/SphericalCap.html or http://en.wikipedia.org/wiki/Spherical_cap or http://keisan.casio.com/has10/SpecExec.cgi?id=system/2006/1223382199
*February 18, 2015*

**math**

I hope Mr. Howard put in the closing brackets. 3(20x + 8) = 60x + 24 4(15x)+6) = 60x + 48 so what is your opinion ?
*February 18, 2015*

**Math**

so what did your calculator say? remember the angle could have been in quadrant IV also. so 360-(whatever your calculator said)°
*February 18, 2015*

**Algebra 2**

sum(7) = (7/2)(2(26) + 6(18)) = 560
*February 18, 2015*

**Algebra 2**

so you want 16+20+24+...100 number of terms = ?? you have an AS, where a = 16 , d=4 term(n) = a+(n-1)d 100 = 16 + (n-1)(4) 84 = 4n - 4 88 = 4n n = 22 so we want S(22) = (22/2)(first + last) = 11(16+100) = 1276
*February 18, 2015*

**Algebra not algabra**

(3a+2)^3 = (3a+2)(9a^2 + 12a + 4) = 27a^3 + 36a^2 + 12a + 18a^2 + 24a + 8 = 27a^3 + 54a^2 + 36a + 8 or , using the binomial expansion = 1(3a)^3 + 3(3a)^2 (2) + 3(3a)(2^2) = 1(2^3) = 27a^3 + 54a^2 + 36a + 8
*February 18, 2015*

**Math**

N = N(M) + N(S) + N(R) - N(M and S) - N(M and R) - N(S and R) + N(M and S and R) = 36+28+12 - 15 - 12 - 8 + 4 = 45 If the question is, How many did not buy any type of book, then it would be 59-45 or 14 You did not state a question. You could draw a Venn diagram and all ...
*February 18, 2015*

**math**

sinØ = 4/5 = .8 Your first angle is correct, so the angle in quad II should be 180-53.13 = 126.87° check with a calculator, also check your second answer to see that it is incorrect.
*February 17, 2015*

**math**

a + ar = 12 a(1+r) = 12 a = 12/(1+r) ar^2 = 16 a = 16/r^2 then 16/r^2 = 12/(1+r) 12r^2 = 16+16r 12r^2 - 16r - 16 = 0 3r^2 - 4r - 4 = 0 (r-2)(3r+2) = 0 r = 2 or r = -2/3 if r = 2, a = 16/4 = 4 ---> ar = 8, but t1 should be > t2, so, no good if r = -2/3 , a = 16/(4/9) = 36...
*February 17, 2015*

**algebra**

area of picture = (4x+3)(3x+5) = 12x^2 + 29x + 15 area of whole thing = (4x+3 +4)(3x+5 + 4) = (4x+7)(3x+9) = 12x^2 + 57x+63 area of border = 12x^2 + 57x+63 - (12x^2 + 29x + 15) = 28x + 48
*February 17, 2015*

**algebra**

let the other endpoint be (a,b) by the midpoint method: (a+7)/2 = 3 a+7 = 6 a = -1 (b+4)/2 = 4 b+4 = 8 b = 4 the other point is (-1,4)
*February 17, 2015*

**math**

The way you typed it ... -4x + 3 = 0 -4x = -3 x = 3/4 This is a vertical line, so its perpendicular is a horizontal line and this one would be y = 5 so you are correct, even though your statement "x = 4/3 undefined" makes little sense.
*February 17, 2015*

**Pre-calculus**

ar^2 + ar^3 = 50 ar^2(1+r) = 50 ---- #1 ar^3 + ar^4 = 100 ar^3(1+r) = 100 --- #2 divide #2 by #1 ar^3/ar^2 = 2 r = 2 in #1: a(4)(3) = 50 12a = 50 a = 50/12 = 25/6 so the first 5 terms are 25/6 , 50/6, 100/6, 200/6, 400/6 check" 3rd + 4th = 50 LS = 100/6 + 200/6 = 300/6 = ...
*February 17, 2015*

**Calculus Chain rule**

first write it as f(x) = 2(9x^5 + 1)^-5 now by the chain rule ... f ' (x) = -10(9x^5 + 1)^-6 (45x^4) = -450x^4/(9x^5 + 1)^6
*February 17, 2015*

**algerbra**

use the distance between two points formula Distance = √( (6-3)^2 + (4+6)^2 ) = .... carry on
*February 17, 2015*

**math**

terms are a , ar, ar^2 ... sum4 = a(r^4 - 1)/(r-1) = 15 sum8 = a(r^8 - 1)/(r-1) = 15 + 240 = 255 divide the 2nd equation by the 1st (r^8-1)/(r^4 - 1) = 255/15 = 17 r^4+1)(r^4-1)/(r^4-1) = 17 r^4+1 = 17 r^4 = 16 r^2 = ±4 , and for reals r = ±2 so the constant ...
*February 17, 2015*

**GEOMETRY**

tanØ = 7√3/21 = √3/3 Ø = 30° so the angles are 30°, 60° and 90°
*February 17, 2015*

**algebra**

let the short piece be x longer piece is x+7 x + x+7 = 12 2x = 5 x = 2.5 short piece is 2.5 longer piece is 9.5
*February 17, 2015*

**calculus**

Here is the area you are finding http://www.wolframalpha.com/input/?i=plot+2y%3D16-x%5E2+%2C+x%2B2y%3D4 Find the intersection of the two graphs, you only really need the x values. take vertical slices. so the height of a slice is (8-x^2/2) - (2 - x/2) = 6 - x^2/2 + x/2 take ...
*February 17, 2015*

**maths**

let the number of terms be n last term: a + (n-1)d = 30 a + (n-1)(3) = 30 a + 3n - 3 = 30 a + 3n = 33 or a = 33 -3n sum of n terms = 135 sum of terms = (n/2)(first + last) (n/2)(a + 30) = 135 a + 30 = 270/n subbing in the previous value of a 33-3n + 30 = 270/n -3n^2 + 63n - ...
*February 17, 2015*

**statistics**

This is a standard question in binomial distribution. I don't know what your tables in your text look like, but I would do: prob (getting 5 heads in 15 flips) = C(15,5)(1/2)^5 (1/5)^10 = 3003(1/2)^15 = 3003/32768 = appr .0916 or your answer of .092 You are correct
*February 17, 2015*

**analytic geometry**

Let's create the equation of your cables using the following data let the vertex be at (0,10) two other points are (300,110) and (-300,110) the equation must be y = a(x-0)^2 + 10 = ax^2 + 10 but (300,110) lies on it 110 = a(90000) + 10 a = 100/90000 = 1/900 y = (1/900)x^2...
*February 17, 2015*

**math**

2l + 2w = 18 l + w = 9 could be any two positive numbers that add up to 9 e.g. 5 and 4 7.5 and 1.5 3 2/5 and 4 3/5 6.123 and 2.877 As you can see there would be an infinite number of possibilities.
*February 16, 2015*

**math**

6log2^3 √64+ 10log3^5 √243 = 6log(8*8) + 10log(243√243) = log 64^10 + log ( (243√243)^10) = log ( (64^10)(243√243)^10 ) = log ( (64^10)(243^15) ) = log (7.0128 x 10^35) = appr 53.85 I suspect a typo
*February 16, 2015*

**calculus**

ds/dt = 64 - 32t , assuming b and d are constants = 0 for a max of s 32t = 64 t = 2 sub back into s s = bd + 128 - 64 = bd + 64
*February 16, 2015*

**Math**

See my reply in your previous post for this problem
*February 16, 2015*

**math**

nickels --- n dimes ---- d quarters --- (76-n-d) 5n + 10d + 25(76-n-d) = 900 5n + 10d + 1900 - 25n - 25d = 900 -20n - 15d = -1000 4n + 3d = 200 , #1 if nickels = d dimes = n quarters is still 76-n-d 5d + 10n + 25(76-n-d) = 800 5d + 10n + 1900 - 25n - 25d = 800 -15n - 20d = -...
*February 16, 2015*

**math**

lavender --- x rose pedals --2x buckwheat --- 10 - 3x 4x + 6(2x) + 3(10-3x) = 3.7(10) 4x + 12x + 30 - 9x = 37 I will let you finish it
*February 16, 2015*

**math**

In descending order it would be 7532 you have them in ascending order since the 5 is in the hundreds position, its value is 500
*February 16, 2015*

**Algebra**

Ok, now that you figured out which choice is linear and which is quadratic, you only had two to choose from. If you sub x = 0 into your choice, I get y = 0-3 which is NOT -6, so ..... same thing for the next one, this time you seem to have guessed correctly
*February 16, 2015*

**Algebra**

#1, correct #2 and #3, both incorrect It asked for a quadratic, you picked a linear each time
*February 16, 2015*

**MAth**

clearly the Pen + calculator cost 50-20.45 = 29.55 pen + calc = 29.55 4.5 + calc = 29.55 calc = 25.05 (no tax ? , wow)
*February 16, 2015*

**Math**

what you are basically asking is how much is a present value of 200,000 worth in 5 years , and in 10 years, at a rate of 6.8% amount after 5 yrs = 200000(1.068)^5 = 277,898.54 change the exponent 5 to 10 for the 10 year part Note: Normally a reverse mortgage consists of ...
*February 16, 2015*

**math**

cost to make the cakes = 200(2.7)= 540 To make a profit of 66% she needs 1.66(540) = 896.40 But she discards 10% of her cakes, so only sells 180 Selling price = 896.4/180 = $ 4.98 check: profit = 4.98(180) - 540 = 356.40 rate of profit = 356.4/540 = .66 or 66%
*February 16, 2015*

**Algebra**

-3x^2 - 18x + 15 since 3x^2 + 18x - 15 = 0 does not have any rational roots since b^2 - 4ac is not a perfect square, it does not factor over the rationals
*February 15, 2015*

**math**

area of a rhomus = (1/2)(product of its diagonals) let the other diagonal be a (1/2)(15a) = 60 15a= 120 a = 8 So let's find the hypotenuse of one of the right-angled triangles formed by the intersection of its diagonals base = 4, height = 7.5 if h is the hypotenuse, h^2 = ...
*February 15, 2015*

**Calculus**

You would now sub those two values into the original equation. The larger answer is your maximum the smaller value is your minimum
*February 15, 2015*

**Algebra 1**

I agree. Unless the coeffiecients are relatively small, I usually don't waste too much time trying to factor it. If the x^2 term has a coefficient of 1, and the x term is even I ALWAYS complete the square, it is much faster than the formula. Otherwise, I do a quick ...
*February 15, 2015*

**Math**

3^12 /(3x3^6) = 3^12 / 3^7 = 3^5 = 243
*February 15, 2015*

**calc**

You must have an idea what the tangent function looks like. As Ø approaches 90° or π/2 from the left, tanØ becomes infinitely large positively. as Ø approaches 90° from the right, it is infinitely negative now look at (x^7 - x^9), as x -->...
*February 15, 2015*

**algebra**

expand first , then collect like terms x - 9x + 10 + 11 = 12 - 6x + 1 -8x + 6x = 13 - 21 -2x = -8 x = 4
*February 15, 2015*

**Math**

number of quarters --- x number of dimes --- 21-x 25x + 10(21-x) = 345 25x + 210 - 10x = 345 15x = 135 x = 9 He has 9 quarters and 12 dimes check: 9(25) + 12(10) = 345 , check!!
*February 15, 2015*

**math**

1.41/100 = 1/x 1.41x = 100 x = 100/1.41 = $70.92 ( your textbook must be from the Clinton era. During the Bush years, it was reversed, the Canadian dollar was worth more. Now under Obama we are slipping again and the US dollar is rising, 1 US = appr 1.18 CND . As you can tell ...
*February 15, 2015*

**math**

since you end up with 12 = 4 , which is false, there is no solution
*February 15, 2015*

**maths(urgent answer pls)**

Still messing around with #2 #3, ∑ k(k+2)(k+4) , where k = 1 to n if you expand this you will get a cubic , so you will have to have ∑ k^3 for k=1 to n equal to (1/4)n^2(n+1)^2 ( I had to look that one up) for the square and first degree terms use the ones I gave ...
*February 15, 2015*

**maths(urgent answer pls)**

I answered the first part in your previous post
*February 15, 2015*

**mathematics**

prob(red, black, red) = (3/10)(7/9)(2/8) = 7/120
*February 15, 2015*

**MATHS(sum of series)**

yes it will Sum(1) = (4(2)(3) - 12(2) + 6)/6 = 1 sum(2) = (8(3)(5) - 24(3) + 12)/6 = 10 sum(3) = 12(4)(7) - 36(4) + 18)/6 = 35 etc. It works! I am sure!
*February 15, 2015*

**MATHS(sum of series)**

I will do the first one We were lucky to have the general term, in most cases you have to find that first Secondly you have to know some basic summation formulas ∑ k ,where k = 1 to n is n(n+1)/2 ∑ k^2 , where k = 1 to n is n(n+1)(2n+1)/6 ∑ c , where k = 1 to...
*February 15, 2015*

**calculus**

I will assume you meant: lim (2x + 1 - cosx)/(3x) then ... = lim ( (2x)/(3x) + 1/(3x) - (1/3)(cosx/x) ) as x --> 0 = lim ( 2/3 + 0 - (1/3)(0) ) = 2/3
*February 15, 2015*

**mathematics**

let the first 3 terms be a , ar , and ar^2 ar = a + 4 ar - a = 4 a(r-1) = 4 a = 4/(r-1) ar^2 = ar + 9 ar^2 - ar = 9 a = (9/(r^2 - r) so 9/(r^2-r) = 4/(r-1) 4r^2 - 4r = 9r - 9 4r^2 - 13r + 9 = 0 (4r - 9)(r - 1) = 0 r = 9/4 or r = 1 if r = 9/4, a = 4/(9/4 - 1) = 16/5 the first 3...
*February 15, 2015*

**math**

.6/1 = 384/x x = 384/.6 = 640 the gas occupies 640 cm^3 in the can volume of can = πr^2 h π(3.2^2)h = 640 h = 640/(10.24π) = 19.89 cm
*February 15, 2015*

**math**

let's pick one particular suit, say the hearts to get the above in that order: prob = (1/52)(1/(51)(1/50)(1/49)(1/48) = 1/311875200 but there are 4 such suits prob(of your event) = 4/311875200 = 1/77968800
*February 14, 2015*