Monday

January 16, 2017
Total # Posts: 37,289

**Algebra**

place the vertex at (0,0) and the focus at (8,0) The directrix will be x = -8 let P(x,y) be any point By definition: ?( (x-8)^2 + y^2) = x+8 square both sides x^2 - 16x + 64 + y^2 = x^2 + 16x + 64 y^2 = 32x so at the point where the dish is 10 ft wide, y = 5 25 = 32x x = 25/32

*November 16, 2016*

**Math**

10,000(1.04)^n = 15000 1.04^n = 1.5 take logs of both sides log 1.04^n = log 1.5 n log 1.04 = log 1.5 n = log 1.5/log1.04 = 10.338.. 10 years will not be enough , so she makes 15,000 or more in the 11 th year for the second question you have an arithmetic sequence with a = ...

*November 16, 2016*

**6 grade math**

no need for guessing, just reverse the steps: the first thing we did was multiply by 2, then subtract 27 to get 407 So everything done in reverse: ( 407+27) divide by 2 = 434 ÷ 2 = 217

*November 16, 2016*

**Algebra**

x e^.06t = 70000 x = 70000/e^(.06(19)) = 22,387.33

*November 16, 2016*

**Statistics**

prob(exactly one boy) = C(7,1)xC(5,4)/C(12,5) = 7(5)/792 = 35/792 prob(exactly 2 boys) = C(7,2)xC(5,3)/792 = 21(10)/792 = 35/132 at least one boy = 1 - prob(all girls) = 1 - 1/792 =791/792

*November 16, 2016*

**Math**

you second equation is x-2055 = .25y , what's with the G ? but y = x x-2055 = .25x .75x = 2055 x = 2740

*November 16, 2016*

**Math**

Did you mean, find cos t ? if so, cos t = 5/?29

*November 16, 2016*

**mathematics**

Did you mean x+y=1 x-y=3 ?? if so, add them to get 2x=4 x=2 now subtract them 2y = -2 y = -1

*November 16, 2016*

**math**

Just translate from English to Math larger number --- x smaller number --- y x-y = 15---> x = y + 15 3x = 8y 3(y+15) = 8y 3y + 45 = 8y 45 = 5y y = 9 , then x = 9+15 = 24 state your conclusion

*November 16, 2016*

**math**

speed of train ---- t km/h speed of car ----- c km/h 120/t + 480/c = 8 15/t + 60/c = 1 times tc tc = 15c + 60t 200/t + 400/c = 25/3 times tc (25/3)tc = 200c + 400t tc = (3/25)(200c + 400t) = 24c + 48t 24c + 48 = 15c + 60t 9c = 12t c = 4t/3 sub into 15/t + 60/c = 1 15/t + 60/(...

*November 16, 2016*

**math**

boys rate = 1/b men's rate = 1/m job done by 2 men and 5 boys in 4 days = 4(2/b + 5/m) = 8/b + 20/m job done by 4 men and 4 boys in 3 days = 3(4/m + 4/b) = 12/m + 12/b 8/b + 20/m = 12/m + 12/b 8/m = 4/b 8b = 4m m = 2b or b = m/2 The man's rate is twice the boy's ...

*November 16, 2016*

**TRIANGLE MATH HELP!!!**

Obviously.

*November 16, 2016*

**TRIANGLE MATH HELP!!!**

clearly 47:29:104 ? 46:30:104, but close and 4 : 6 : 8 ? 5.6 : 8 : 11 because: 5.6/4 = 1.4 8/6 = 1.333... 1.375 which answer matches my conclusion

*November 16, 2016*

**Math Help!!!**

6/202.5 = x/52.5 202.5x = 6(52.5) 202.5x = 315 x = 315/202.5 = 3150/2025 = 14/9 or 1 5/9 or 1.5555.... take your pick 1.555... rounded to one decimal is 1.6

*November 16, 2016*

**Math Help!!!**

set up a simple ratio and solve for x 6/202.5 = x/52.5

*November 16, 2016*

**Calculus**

hint: What is the derivative of secx ??

*November 16, 2016*

**Ravindra bharathi school Maths**

Did you mean 1 m , 23 cm? which is 123 cm adding 21 cm gives her 144 cm (tall 10 year old girl, did I mis-read your question?)

*November 16, 2016*

**Algebra**

Retype after correcting the English.

*November 16, 2016*

**math**

one number --- 2x , (avoiding fractions) the other ----- x + 5 (2x)^2- (x+5)^2 = 17 4x^2 - x^2 - 10x -25 - 17 = 0 3x^2 - 10x - 42 = 0 x = (10 ± ?604)/6 = (5 ± ?151)/3 2x = .... x+5 = ... it works, I checked on my calculator

*November 16, 2016*

**Maths**

If I read this correctly, we would get: 1, 4, 5, 10, 20, 40, 80, ... in effect, each term is twice its previous term from the 4th term on Where does the number 2016 come in? clearly not in this sequence. suppose my term start with 1, 2 , then we get 1,2, 3, 6, 12, 24, , again ...

*November 16, 2016*

**Math**

6n = 8p or n = 4p/3 n = p+3.5 4p/3 = p + 3.5 times 3 4p = 3p + 10.5 p = 10.5

*November 16, 2016*

**Maths**

new length = 1.2(50) or 60 m new area = 2340 new width = 2340/60 = 39 increase in width = 9 m

*November 16, 2016*

**math**

I did the previous one for you. Do be successful in this topic you simply MUST know how to do this type of trivial question. They don't come any easier than this one. Show me the steps you would take to solve this problem.

*November 15, 2016*

**math**

number of ways to get 3 tens and 2 kings = C(4,3) * C(4,2) = 24 prob(of your event) = 24/C(52,5) = 24/2598960 = 1/108290

*November 15, 2016*

**math. PLEASE HELP.**

Following your description I got sin 29° = opp/hyp = 4.6/c csin29 = 4.6 c = 4.6/sin29 = 9.48826.. or appr 9.5 I don't know how you got 2.5

*November 15, 2016*

**disagree - math**

Batting "order" implies that the order they play is important, so 13 P 9 = 13*12*11*10*9*8*7*6*5 = ....

*November 15, 2016*

**Math**

dividing by: 2's leaving one remainder: 3 5 7 9 11 13 15 ... odd numbers 3's leaving one remainder: 4 7 10 13 16 19 22 25 28 ... common difference 3 So far: 7 13 19 25 31 37 43 49 .... (common difference is 6) 4's leaving one remainder: 5 9 13 17 21 25 29 33 37 41 ...

*November 15, 2016*

**Algebra**

The only condition your equation states is that y = 3 That is, there is no condition on x, so the x can be anything. e.g. (4,3), (1,3), (506,3), (12.34, 3), (?,3), .... the result is a horizontal line 3 units above the x-axis, that is, the y = 3

*November 15, 2016*

**Geometry**

What makes you say it is (9,5) ???

*November 15, 2016*

**Algebra2**

correct

*November 15, 2016*

**Pre-cal**

sec x = 2csc x 1/cosx = 2/sinx sinx = 2cosx sinx/cosx = 2 tanx = 2 yes, I would use tan^-1 (2), but make sure your calculator is set to radians, (DRG key) Also remember that the tangent is positive in quads I and III tan^-1 (2) = appr 1.107 x = 1.107 or x = ?+1.107= appr 4.249

*November 15, 2016*

**math**

so in 7 years ? amount = 3000(1.05)^7 = ....

*November 15, 2016*

**Algebra**

2a = 4 a = 2 e = c/a c/2 = 3/2 c = 3 in a hyperbola: a^2 + b^2 = c^2 4 + b^2 = 9 b^2 = 5 a^2 = 4 centre is (-2,3) (x+2)^2 /4 - (y-3)^2 /5 = 1

*November 15, 2016*

**Algebra**

g(x) = x^2 - 2 g(-2) = (-2)^2 - 2 = 4-2 = 2

*November 15, 2016*

**Maths**

smaller angle --- x larger angle --- x+20 x + x+20 + 90 = 180 2x = 70 x = 35 the angles are 35° , 55° and 90°

*November 15, 2016*

**Trigonometry**

taking your data: y = (4/7)sin (x + 3?) + 1 when x = ?/2 y = (4/7)sin(?/2+3?) = 1 = (4/7)sin (7?/2) + 1 = (4/7)(-1) + 1 = 3/7

*November 15, 2016*

**MATH 123**

1((1/2)^(t/5730) = .55 (.5)^(t/5730 = .55 take log of both sides log (.5)^(t/5730 = log .55 (t/5730) log .5 = log .55 t/5730 = log .55/log .5 t = 5730(log .55/log .5) = appr 4942 years

*November 15, 2016*

**math**

x + y ? 20 9x + 12y ? 200 whatever graph they give you, there should be one with the region below x+y = 20 shaded in AND the region above 9x + 12y = 200 shaded in. It should look something like this: http://www.wolframalpha.com/input/?i=plot+x+%2B+y+%3D+20+,+9x+%2B+12y+%3D+200...

*November 15, 2016*

**math**

When you have a function such as P(x) = 2(x-3)(x-4) you could also write it as y = 2(x-3)(x-4) So when they speak of the zeros of the function, they are really describing the x's that make y = 0 that is: 2(x-3)(x-4) = 0 Now think about the answer of 0 after a ...

*November 15, 2016*

**maths**

fog = f(g(x)) = f(2x-3) = (2x-3)^2 + 3(2x-3) + 1 = 4x^2 - 12x + 9 + 6x - 9 + 1 = 4x^2 - 6x + 1 now do gog in the same way

*November 15, 2016*

**Math**

A : B = 5:11 = 10 : 22 = ... = 10x : 22x A : B : C = 2:3:15 = 10:15:75 = ... = 10x:15x:75x in solution X we have 10x/(22x) of A so amount of A in 400 L ofX is (10/22)(400) = appr 181.8 L in solution Y amount of C in 400 L = 75x/(100x)(400) = 300 L

*November 15, 2016*

**maths**

qD(9) = 8000/(81+1) = appr 97.56 qD(8.5) = 8000(72.25+1) = appr 109.22 So, what do you think?

*November 15, 2016*

**algebra**

just translate .... four times a number --- 4x fourteen times its reciprocal --- 17(1/x) or 17/x the sum of ---> + is 15 ----> = 15 so: 4x + 17/x = 15 How easy was that?

*November 15, 2016*

**Algebra**

woman's rate ---- 1/x man's rate ----- 1/(x-5) , where x > 5 combined rate = 1/x + 1/(x-5) = (x-5 +x)/(x(x-5)) = (2x-5)/(x^2 - 5x) (2x-5)/(x^2 - 5x) = 1/6 x^2 - 5x = 12x - 30 x^2 - 17x + 30 = 0 (x-15)(x-2) = 0 x = 15 or x =2 , but x > 5 x = 15 The woman can do ...

*November 15, 2016*

**Math**

1-(-2)^2*(-1)^3 = 1 - 4(-1) = 1 + 4 = 5

*November 15, 2016*

**maths**

Make your sketch. Method 1, complete the parallelogram and find the diagonal x^2 = 5^2 + 3^2 - 2(5)(3)cos 150° = 59.9807... x = appr 7.74 (exact value: x^2 = 34 + 30?3/2 = 34 + 15?3 x = ?(34 + 15?3) ) method 2 place vector P along the horizontal so vector P = (5,0) vector ...

*November 15, 2016*

**Algebra**

same thing e.g. (1/2)(12) = 6 12/2 = 6 as to your question, mom's age ---- x Rowena's age -- x/2 8 years ago: mom ---- x-8 Rowena -- x/2 - 8 x/2 - 8 = (1/3)(x-8) times 6, the LCD 3x - 48 = 2(x-8) 3x - 48 = 2x - 16 x = 32 Mom is 32, Rowena is 16 check: 8 years ago, the ...

*November 15, 2016*

**math**

Arggghhhh!

*November 15, 2016*

**Maths**

How about this approach? A:B = 2:3 or 6:9 B:C = 9:5 ---> notice the value of B is the same so A:B:C = 6:9:5 or 6x:9x:5x 6x+9x+5x = 400 20x = 400 x = 20 so A got 6(20) = 120 B got 9(20) = 180 C got 5(20) = 100

*November 15, 2016*

**Math**

I am going to assume you meant (2x-7)/4 - (x-6)/7 = 0 then (2x-7)/4 = (x-6)/7 multiply both sides by 28, the LCD 7(2x-7) = 4(x-6) 14x - 49 = 4x - 24 10x = 25 x = 25/10 = 5/2 or 2.5 or 2 1/2

*November 14, 2016*

**Math**

50x^4 / (12x) = 25x^3 /6 or (25/6)x^3

*November 14, 2016*

**thomas middle such**

it is less than 300 --> 1xx or 2xx the hundreds digit is 3 less than the ones digit ---1x4 or 2x5 the tens digit is 5 more than the hundreds digit ---> 164 or 274 the sum if the digits is 11 ----> 164

*November 14, 2016*

**algebra**

original: width --- x length --- 5x , (it said so) new dimensions: length = 5x - 3 width = x+10 perimeter = 2* width + 2*length = 2(x+10) + 2(5x-3) = 374 2x + 20 + 10x - 6 = 374 12x = 360 x = 30 So the original rectangle had a width of 30 m and a length of 150 m

*November 14, 2016*

**algebra**

4b/2 + 3 = 11 + b 2b + 3 = 11 + b, since 4/2 = 2 2b - b = 11-3 b = 8 or 4b/2 + 3 = 11 + b multiply every term by 2 4b + 6 = 22 + 2b 4b - 2b = 22 - 6 2b = 16 divide both sides by 2 b = 8

*November 14, 2016*

**math**

the effective distance: 16 km east and 8 km north ---> right-angled triangle hint: Pythagoras

*November 14, 2016*

**math**

Poorly worded question. Are we to assume that some questions were skipped, and no reward or penalty for skipped questions? I will assume that. rights ---- x wrongs --- y skipped -- 40-x-y) 5x - 3y + 0(40-x-y) = 70 5x - 3y = 72 y = (5x-70)/3 , clearly 14 ? x ? 40 , x+y ? 40 ...

*November 14, 2016*

**Math**

Now: Benny ---- x years Apple ---- 38-x 6 years ago: Benny ---- x-7 Apple ----- 38-x - 7 = 31-x 31-x = 3(x-7) solve for x, and sub into my definitions

*November 14, 2016*

**Maths**

let the perpendicular height be 4x let the slant height be 5x (4x)^2 + 6^2 = (5x^2 16x^2 + 36 = 25x^2 carry on, of course you would reject the negative value of x after taking the square root at the end.

*November 14, 2016*

**Maths**

Think of the 5 kids standing in a row, and in each row changing positions 1 ---> 3 2 ---> 5 3 ---> 1 4 ---> 2 5 ---> 4 At the start,,,: 1 2 3 4 5 ---> A B C D E after 1 round: 3 4 1 5 2 ---> C D A E B after 2 round: 1 5 3 2 4 ---> A E C B D after 3 ...

*November 14, 2016*

**math**

depends where you want the water spout to be. It would make sense to have the spout at the origin. Then the zeros of the function would be (0,0) and (8,0) and the vertex would be at (4,6) height = a(x - 4)^2 + 6 but (0,0) lies on it, thus: 0 = a(0-4)^2 + 6 16a = -6 a = -3/8 ...

*November 14, 2016*

**Aljebra**

original number in first box --- x original number in 2nd box --- 123-x after shift: first box ----- x-10 2nd box --- 123-x + 10 = 133-x 133-x = 2(x-10) solve for x

*November 13, 2016*

**Math**

3?(x - 1) + 6 when x = 26 = 3?25 + 6 = ....

*November 13, 2016*

**pre algebra**

adult tickets ---- x children tickets --- 2x + 15 solve for x: 12x + 5(2x+15) = 1920

*November 13, 2016*

**pre algebra**

follow the same method and steps I just showed you in your other posts. The two questions are of the same structure.

*November 13, 2016*

**intermediate maths**

granddaughter's age---- x James' age --------- 6x 2 years from now: granddaughter's age --- x+2 James' age ---------- 6x + 2 6x+2 = 5(x+2) solve for x

*November 13, 2016*

**Algebra**

speed of slower rider --- x km/h speed of faster rider ---- 2x km/h distance gone by slower = 3(x) = 3x distance gone by faster = 3(2x) = 6x 3x + 6x = 90 9x = 90 x = 10 rate of slower rider = 10 km/h rate of faster rider = 2(10) = 20 km/h

*November 13, 2016*

**Calculus**

let the point of contact be P(a,b) let A be (1,7) slope of AP = (b-7)/(a-1) the closest point would be where the tangent at P is perpendicular to AP 2y dy/dx = 1 dy/dx = 1/(2y) so at P, the slope of the tangent is 1/(2b) so (b-7)/(a-1) = -2b b-7 = -2ab + 2b -b = -2ab + 7 2ab...

*November 13, 2016*

**math**

In a parallelogram Abcd angle add ??? side an ???? e ????? x+y ???? wow!

*November 13, 2016*

**Math**

Just follow the definition: a*b means 3a^2+b 3*1 means 3(3^2) + 1 = .....

*November 13, 2016*

**Math**

number correct --- x , 0 ? x ? 20 number wrong ---- y number skipped ---- 20-x-y 5x - y + 0 = 72 y = 5x - 72 y ? 0 if x = 14, y = -2 , not possible if x = 15 , y = 3 , skipped = 2 if x = 16, y = 8 , not possible , x+y>20 so he got 16 right, 8 wrong, and skipped 2 check: 5(...

*November 13, 2016*

**Math**

not arithmetic nor geometric gave up and checked with Wolfram found: term(n) = (7(3^n) - 3)/6 http://www.wolframalpha.com/input/?i=pattern+%7B3,+10,+31,+94%7D quite obscure, perhaps more terms would have helped.

*November 13, 2016*

**Math**

mmmhhhh when x=1 , 3+2x = 3+2(1) = 5 when x=2, 3+2x = 3+2(2) = 7 when x = 3 ..... continue

*November 13, 2016*

**Math**

number of girls --- x number of boys --- (5/11)x x - (5/11)x = 114 (6/11)x = 114 x = 114(11/6) = .... take over

*November 13, 2016*

**Math**

1:2:1/2 = 2:4:1 -----> ratios usually are not expressed in fraction form let their shares be 2x, 4x, and x but x = 48 so 2x = 96 and 4x = 192 add them up

*November 13, 2016*

**Calculus**

You did not do exactly the same, your slope was -3/5, different from mine. (another example of why I prefer traditional class room instructions, where the learning of math is not just "answer based" )

*November 13, 2016*

**Calculus**

How did you get the slope to be -3/5 ?? let the x-intercept be A(a,0) and the y-intercept be B(0,b) label point (3,5) as P By ratios in similar triangles: (a-3)/5 = 3/(b-5) ab-5a-3b+5 = 15 b(a-3) = 5a b = 5a/(a-3) Area of triangle = (1/2)ab = (1/2)(a)(5a/(a-3) ) = 5a^2/(2a-6) ...

*November 13, 2016*

**Math**

right now: x + 7x = 976 x= 122 Aaron has 122 cards and Ben has 854. after the give-away of k cards: ben has 854-k Aaron has 122+k Aaron has 3 times as many as Ben 122+k = 3(854 - k) 122+k = 2562 - 3k 4k = 2440 k = 610 check: after the exchange Ben has 854-610 = 244 Aaron has ...

*November 12, 2016*

**Maths**

3^9 + 3^12 + 3^15 + 3^n = 3^9(1 + 3^3 + 3^6 + 3^(n-9) ) = 3^9(757 + 3^(n-9)) 3^9 is a perfect cube, so all we need is (757 + 3^(n-9)) to be a perfect cube, clearly n >9 perfect cubes past 757 with 3^(n-9) as the 2nd number: 1000 243 <---- well, that was lucky 1331 574...

*November 12, 2016*

**Calculus**

let the height be h then h^2 + b^2 = 20^2 h = (400-b^2)^(1/2) Area = (1/2)(bh) = (1/2)(b)(400 - b^2)^(1/2) d(Area)/dt = (b/2)(1/2)(400-b^2)^(-1/2) (-2b db/dt) + (1/2)(db/dt)(400 - b^2)^(1/2) = -b^2 (db/dt)/?(400-b^2) + (1/2)(db/dt)?(400-b^2) when b = 11 and db/dt = 4 d(Area)/...

*November 12, 2016*

**math**

number of ways to give the fruits = 5!/(3!2!) = 10 (you could list them) Bananas at least two days in a row: BABAB is the only case where two or more B could not be together. Look at your list from above prog(at least two B's in a row) = 9/10

*November 12, 2016*

**maths**

Susan's age now ---- x Mary's age now ------3x Three years ago: Susan ---- x-3 Mary ----- 3x-3 x-3 + 3x-3 = 22 continue

*November 12, 2016*

**Algebra**

good road ---- x km poor road ----- 48-x km time on good road = x/72 time on poor road = (48-x)/48 x/72 + (48-x)/48 = 3/4 times 144 , the LCD 2x + 3(48-x) = 108 carry on, easy from here

*November 12, 2016*

**Maths**

without a calculator... let a=20142014 then 20142015 = a+1 then 20152015 = a + 1 + 1000 = a+1001 then 20152014 = a+1000 20142015×20152014 – 20142014 ×20152015 = (a+1)(a+1000) - a(a+1001) = a^2 + 1001a + 1000 - a^2 - 1001a = 1000

*November 12, 2016*

**Algebra**

2x^3 - 5x^2 - 5x - 1 = 0 let f(x) = 2x^3 - 5x^2 - 5x - 1 try f(1) = 2 - 5 - 5 - 1 ? 0 try f(-1) = -2 - 5 + 5 - 1 ? 0 try f(1/2) = 1/4 - 5/4 - 5/2 - 1? 0 try f(-1/2) = -1/4 - 5/4 + 5/2 - 1 = 0 , yeahh! so (2x + 1) is a factor and x = -1/2 by long algebraic division, which I ...

*November 11, 2016*

**Math -fractions word problems**

total number of students ---- x number of boys ----- (3/7)x number of girls ------(4/7)x (4/7)x = (3/7)x + 4 times 7, the LCD 4x = 3x + 28 x = 28 boys: (3/7)(28) = 12 girls = 28-12 = 16

*November 11, 2016*

**intergrated science**

I will assume that Calculus is part of your integrated science course. a = 2 then v = 2t + c at the beginning of the observation, t = 0 , v = 24 so 24 = a(0) + c ----> c = 24 v = 2t + 24 when t = 8 v = 2(8) + 24 = 40 m/s or, simply .... for each of the 8 seconds the ...

*November 11, 2016*

**calculus**

your values of x = -2, 3 are the x-intercepts, and you don't need a derivative to find them dy/dx = (x-3)(2/3)(x+2)^(-1/3) + (x+2)^(2/3) = (1/3)(x+2)^(-1/3) [2(x-3) + 3(x+2)] = (1/3)(5x)(x+2)^(-1/3) = 0 for a max/min of y ----> 5x = 0 or (x+2)^(-1/3) = 0 ---> no way ...

*November 11, 2016*

**math- Trigonometry**

I agree with Scott. For the given date, the calculations are correct. In reality, the question is absurd. Using Pythagoras, the height of the lighthouse would have to be appr 8.9 km high. and, using our given angle of 65.91..° tan 65.91 = height/4 height = 4tan 65.91 = ...

*November 11, 2016*

**Math**

or 15 machines 15 minutes to make 500 raviolis 75 machines 15 minutes to make 2500 raviolis 75 machines 15(2.4) minutes to make 2500(2.4) raviolis 75 machines 36 minutes to make 6000 raviolis (the 2.4 comes from 6000/2500)

*November 11, 2016*

**maths**

I assume you are solving? from the 2nd: y = -2x-4 sub into the first 3x - 2(-2x - 4) = 1 3x + 4x + 8 = 1 7x = -7 x = -1 back into y = -2x - 4 y = -2(-1) - 4 = -2 x = -1 , y = -2

*November 11, 2016*

**Math**

Assuming that x is the length of the missing parallel side ... area of trapezoid = (x+15)(10)/2= 5x + 75 area of triangle = (1/2)(15)(10) = 75 5x + 75 < 2(75) 5x < 75 x < 15 but clearly x has to be positive 0 < x < 15 looks like a common sense type of question ...

*November 11, 2016*

**finite math**

mortgage after downpayment = 140,000 i = .09/12 = .0075 n = 30(12) = 360 payment = p p(1 - 1.0075^-360)/.0075 = 140000 p(124.2818657.) = 140000 p = $1126.47

*November 11, 2016*

**finite math**

Follow the same steps I just showed you here http://www.jiskha.com/display.cgi?id=1478848733

*November 11, 2016*

**Math**

1/6 of the 3/2 pepperoni's remain or 1/4 this is (14)/4 or 1/16 of the original amount

*November 11, 2016*

**Math**

distance covered in one rotation = 25? inches 65 miles/hr = 65*12*5280 inches/hour = 65*12*5280/3600 inches/sec number of rotations = 65*12*5280/3600 ÷ (25?) = 14.56.. / sec or appr 15 rotations per second check: distance in 1 second = 14.56*25? = appr 1143.5 inches = ...

*November 11, 2016*

**Statistics**

prob(ace) = 4/52 = 1/13 prob(5 aces with card replaced each time) = (1/13)^5 = ....

*November 10, 2016*

**Math**

did you notice that the third difference is 3 ? So it is a cubic messing around a bit I got term(n) = (n^3 - n^2 - 4)/2 so term(6) = (216 - 36 - 4)/2 = 88

*November 10, 2016*

**math**

68/104 = 17/26 This question has two correct choices as answers. Poorly designed question.

*November 10, 2016*

**matha**

What part of my previous reply to your same question did you not like ? http://www.jiskha.com/display.cgi?id=1478784506

*November 10, 2016*

**Math**

This year: number of middle schoolers --- 2x number of high schoolers ----- 7x but 2x = 18 x = 9 So this year there are 18 middle schoolers, and 63 high schoolers. Total = 81 Since all we know from the previous year is the ratio of 1:8 , and there were more last year: possible...

*November 10, 2016*