# Posts by Reiny

Total # Posts: 38,777

math
notice that here https://istrumpatmaralago.org the wording makes sense. Is that what you mean? Then follow the method that Steve used in the question.

math
suppose each part was x and then apply changes 1st: x-4 2nd: x+5 3rd: x/2 4th: 3x x-4 + x+5 + x/2 + 3x = 155 5.5x = 154 x = 28 the four parts are 24, 32, 14, and 84 I find it hard to understand what the question really is. Very confusing wording.

math
circumference = 7700/14 ft = 550 ft since C = 2?r 2?r = 550 r = 275/? area = ?(275/?)^2 = (275^2)/? = appr 24072.2 ft^2 I waited to do any calculations to the very end, then used ? of my calculator.

Math
I did not get that, show me your work to see where you went wrong.

math
RS = cot^2 a (1 - csc^2 a) = cot^2 a (-cot^2 a) = - cot^4 a ? LS not true, check your typing

Math
no obvious repeat can be seen in the decimal, but the "..." shows an infinite number of decimals, so as it stands I would label it irrational

Calculus
I agree with you. I also found the 2nd derivative to be (1/2)t^2 - 3t + 4 and the third derivative to be t - 3 since the 2nd derivative is a quadratic opening upwards, you would have a minimum at t = 3 Could be a misprint

Math check?
I read that as f(x) = x^2 - x - 6x^2 - 8x + 15 = -5x^2 -9x + 15 -5x^2 -9x + 15 = 0 5x^2 + 9x - 15 = 0 use the quadratic formula to solve. Both zeros are irrational Somehow I suspect you have a typo in your equation.

Math
Notice that is simply a geometric series, where a = 1/5, r = 1/5 since Sum(all terms) = a/(1-r) = (1/5)/(4/5) = 1/4 , it clearly converges What made you think it diverges? What have you studied about diverging and converging series? ( simply adding the first 4 already gives us...

Algebra 2
assuming you meant f(x) = 2sin(x^2) - 1 look at the graphs of these two: http://www.wolframalpha.com/input/?i=plot+y%3D2sin(x%5E2)%E2%88%921+,+y%3D2sin(x)%E2%88%925 none of the given answers are correct. The problem is the x ---> x^2 There is compression, but at an ...

Math help....
Unusual to have an x in a polar form, was expecting 3r = -6cosØ , will assume that. recall that cosØ = x/r so 3r = -6x/r 3r^2 = -6x x^2 + y^2 = -6x for 3xy = 5 cosØ = x/r ---> x = rcosØ and sinØ = y/r --> y = sinØ 3(rcosØ...

Math Help ASAP
All 3 are correct

Algebra 2 helppppp
correct

Math
Actually, the way you typed the question, you are correct According to the order of operation, each term in the bracket is divided by 2, then multiplied by m^3 multiplication and division is done in the order they occur. What the question probably meant was (-6m^9 - 6m^8-16m^6...

Math
after 1 year ---- 950000(.9) = after 2 years ----950000(.9)^2 .. after 5 years ---- 950000(.9)^5 = ....

Algebra
amount invested at 4% --- x amount invested at 5% ---- y .04x + .05y = 1000 4x + 5y = 100000 , #1 reversed: .05x + .04y = 1050 5x + 4y = 105000 , #2 solve these two equations.

Algebra
unit cost price .... x return = 1.3(8) + .6(92) = 65.6 percentage = 65.6/100 = 65.6% So there is a loss of 34.4% test: suppose he bought them at \$1 per egg cost price = \$100 return = 8(1.30) + 92(.60) = 10.40 + 55.20 = \$65.60 He lost \$34.40 out of the \$100 he spent. So loss is...

math question
You already stated the answer. It is 9/16 of its original area. You probably meant to ask: How do the sides of the reduced triangle compare to the original sides? Remember what I told you in a question similar to this? "The area of similar shapes is proportional to the ...

Math
total members ---- x girls ------ (3/8)x or 3x/8 girls that are 6 graders = (2/5)(3x/8) = 6x/40 = 3x/20 so (3/20) of the members are 6 grader girls

math
Go with Plumpycat's table, I started mine with the wrong time at 1:00 , DUH here is an easy way 80 false minutes = 60 reals at 6:00 false times , 300 false minutes have passed 80/300 = 60/x 80x = 18000 x = 225 real minutes = 3 hours and 45 minutes add that to 1:00 ---->...

math
let's make a chart, RT = real time, FT = false time time expressed as an fraction number since 20 minutes = 1/3 hour .... RT - FT 1.0 1+1/3 = 4/3 --> 1:20 2.0 4/3+4/3 = 8/3 --> 2:40 3.0 12/3 = 4.0 --> 4:00 4.0 16/3 --> 5:20 5.0 20/3 --> 6:40 So the real time...

math
let's pretend that a "cog" is a unit of distance so in 160 revs the second wheel went 160(54) or 8640 cogs in that same time the first wheel had to do 8640/32 or 270 revolutions it did that in 45 seconds, so it went 270/45 or 6 revolutions per second ---> so ...

Statistics
ok, ok I have answered quite a few for you now. You have shown no ideas or steps of your own. How do you think you should start this one?

Statistics
Assuming that he can answer them in any order and that he is not restricted to anwering only 3 of the first 5, that is, he could answer all of the first five. step one: number of ways to answer the obligatory questions = C(5,3) = 10 So now he has to answer 7 more of any of the...

algebra
First of all, I would multiply each term by 100 519(y-10) +610 = 300(y - 6.6) + 430 519y - 5190 + 610 = 300y - 1980 + 430 look, no decimals, no fractions, take over

word problem
Very simple. When is 21 + .18m = 24.44 + .15 m ? or 2100 + 18m = 2444 + 15m just solve for m at the value of m, they are equal, so you decide for miles above or below that value.

Math
What is C(6,3)? = 6!/(3!3!) = (six choose 3, a term in combination study)

Statistics
you have 4 books One of two specific books have to come first, after that it, it doesn't matter, so number of ways = 2 x 3 x 2 x 1 = 12

College Algebra
2x^2 + 5x + 7 = 0 Just do it.

College Algebra
This is modelled by a downwards opening parabola. h(t) = -10t^2 + 440t = -10t(t - 44) so the x-intercepts are 0 and 44, which means that the vertex lies half way between them i.e. x = 22 find h(22) This worked nicely since there was no constant.

Calculus
This is the same question I did for you before. Just change the numbers. http://www.jiskha.com/display.cgi?id=1493856619

geometetry
looks like the same problem here: http://www.jiskha.com/display.cgi?id=1493855490

Statistics
Make a table, using rows from 1 to 6, and columns from 1 to 6 Fill in the sums, eg. row2, column3 will be 5 Count how many add up to 8 Find the probability of getting a sum of 8

Math
You got it!!

Math
no and no There are 7 balls in the bag of which 3 are black So the prob of drawing a black the first time is 3/7 So what will happen the second draw?? What is the answer to the first question I asked you?

Math
Why do you think it is A? are you guessing? What is the prob of getting a black in the first draw?

Math
Do you think the balls remember what happened to them on the first draw when you do the second draw ? What is the prob of drawing a black ball the first time?

math
Before the giving: Lala has x Anna has x+15 After the giving: Lala has x+60 Anna has x+15 x+60 = 3(x+15) solve for x, sub into my definitions

Statistics
number of ways to choose 2 from 5 items = C(5,2) = 10 number of ways to choose 1 bolt from3 and 1 nut from 3 = C(3,1) * C(3,1) = 9 prob(your event) = 9/10

Statistics
I don't suppose that the order of assigning the books matters so we have combinations. "a" can be assigned books in C(10,5) ways, leaving 5 books for "b" who needs 3, that would be C(5,3), leaving the last 2 books to "c", number of ways = C(10...

Active math's
Nope, I can't. First of all your statement does not make any grammatical sense and your spelling is atrocious. Secondly, consecutive numbers are integers that are one unit apart. So algebraically your three numbers would be x, x+1, and x+2 then x = x+2 = 72, which has no ...

Calculus
y1 = 1.4 -2(x-13) , y2 = 1.4 -2(-x+13) y1 = 27.4 - 2x , y2 = -24.6 + 2x intersection: 2x - 24.6 = -2x + 27.4 4x = 52 x = 13 , then y = 1.4 ---> range is 0 to 1.4 y1 = 27.4 - 2x ---> x = 13.4 - y/2 --> outer radius y2 = -24.6 + 2x --> x = 12.3 + y/2 --> inner ...

geometry
split the trapezoid into a rectangle of 9 by h, and a triangle with base 9, height h, and hypotenuse 15 by Pythagoras: h^2 + 9^2 = 15^2 h = 12 Now you have all the dimensions, add up the two areas

Math
number of children --- 3x number of adults ----- 2x , notice 3x : 2x = 3:2 3x+2x = 500 x = 100 so we would have 300 children and 200 adults price of adult ticket ---- x 300(2) + 200x = 1600 solve for x

math
#1 checking for the given roots P(1) = 1 - 8 + 23 - 28 + 12 = 0 yup, x-1 is a factor P(2) = 16 - 64 + 92 - 56 + 12 = 0 yup, x-2 is a factor now divided x^4-8x^3+23x^2-28x+12 by (x-1) to get a cubic, then divide that cubic by (x-2), leaving you with a quadratic expression set ...

math
A:B:C = 1:2:3 = 12x : 24x : 36x for A: acid:water = 1:5 = (1/6)12x : (5/6)12x = 2x : 10x for B: acid:water = 3:5 = (3/8)24x : (5/8)24x = 9x : 15x for C: acid:water = 5:7 = (5/12)36x : (7/12)36x = 15x : 21x now pouring this into one container in 1:2:3 from A we are getting 2x ...

math
we don't know the rate, let it be r A will get only 1/2 years interest = (1/2)(r)(5000) = 2500r B will get a full year on his 10,000 = 10000r C will get 7500r + (1/2)(r)(5000) = 10000r 2500r + 10000r + 10000r = 9000 22500r = 9000 r = .4 so C will get 10,000(.4) = 4000 40% ...

Algebra2
The primary solutions are .71 and ?-.71 or .71 and 2.43 so I would state it as .71 + 2?n and 2.43 + 2?n , which is a variation of B so you are correct, but I find their choice puzzling (notice -3.85 + 2? = 2.43)

8th gr algebra
your first card could be 52 different ones, leaving 51 different ones to draw for you second, then 50 for the third and 49 for the fourth, and finally 48 for the last. so what is 52(51)(50)(49)(48) = ...

Algebra II
for the y-intercept, let x = 0 f(0) = e^(0-0+20) - 1 = e^20 - 1 that is really big, appr 485,165,194 for the x-intercept, let y = 0 e^(x^2-9x+20)-1 = 0 e^(x^2-9x+20) = 1 e^(x^2-9x+20) = e^0 so x^2 - 9x + 20 = 0 (x-5)(x-4) = 0 x = 5 or x = 4

Math
I agree with Scott time for first leg = d/10 time for return leg = d/8 total time = d/10 + d/8 = 9d/40 avg rate = total distance/total time = 2d/(9d/40) = 2d(40/9d) = 80/9 mph distance = (27/60)(80/9) = 4 miles So she ran 4 miles in total. check: 2 miles at 10 mph = 2/10 hrs 2...

If x=-4 is one of the solutions, then x+4 must be a factor of x^3 - 28x - 48 so do a long division. You must get a quadratic with no remainder. solve that quadratic = 0 to get the other two zeros. hint: the remaining quadratic factors to give 2 more integer solutions.

math
I will do a) you do b) in the same way f(g(x)) = f(x/2 + 4) = 2(x/2 + 4) - 8 = x , mmhhhh - interesting!

Algebra 1
y = .4x + 7 creates ordered pairs of the type (x,y) so at the y-intercept, it would be (0,7) and what does (0,7) stand for ? or since x is the number of days since it was cut, what would be x right after you cut the grass??

Math
a = ln2 ---> 2 = e^a b = ln11 ---> 11 = e^b ln(3?22) = ln3 + (1/2)ln22 = ln3 + (1/2)(ln11 + ln2) = ln3 + (b+a)/2 are you sure you typed it correctly? I suspect we were asked for ln (2?22)

MATH
You could just leave it like that, or x^2 y + y^3 = 3x or y(x^2 + y^2) = 3x just curious. Did they actually have tanx in the polar form and then asked for the cartesian form? I would have expected something like r^2 = 3/tanØ If it actually was r^2 = 3/tanx then it would...

arc length = rØ, where r is the radius and Ø is the central angle in radians. 255° = (255/180)? radians = 17?/12 17?/12 r = 52 r = 52(12)/(17?) = 624/(17?) m = 11.6838... m using my calculator value of ? or even more simple: 2?r/360 = 52/255 2?r = (52/255)(...

if f(t)=2150?(1.04)t then the 2150 is the value of f(t) when t = 0 that is, 2150 is the initial value you can tell your answer is incorrect by subbing in t = 2 f(2) = 2150(1.04)^2 = appr 2325 ? 2150

Maths
Steve did this same question here: http://www.jiskha.com/display.cgi?id=1493739139

Maths
Ms Sue wins the reply of the day reward.

Calculus I
Steve got the same answer in 2 different ways. I must have made an error in my arithmetic, too lazy to find it

Calculus I
let the position on the x-axis be (x,0) and the position on the y-axis by (0,y) the article is moving to the right on the x-axis at 2 units/s ---> dx/dt = 2 the article is moving DOWN the y-axis at 3 units/s ---- dy/dt = -3 according to my diagram, at any moment of t ...

Maths
Finally, even after you changed your name 3 times first subtract them: -2x -4y + 4=0 x + 2y + 2 =0 x = -2-2y sub into the first: (-2-2y)^2 + y^2 - 10(-2-2y) - 8y +18=0 4 + 8y + 4y^2 + y^2 + 20 + 20y - 8y + 18 = 0 5y^2 + 20y + 38=0 y = (-20 + ?-360)/10 , which is not a real ...

MATH
number of kid's tickets --- x number of adults ------- 2x 10x + 25(2x) = 1800 solve for x, sub into my definitions

precalculus
we know the amplitude, we know the vertical shift but we don't know the frequency. Not enough information to write a specific equation.

Maths
Sounds like a repeat of this without correcting the error. http://www.jiskha.com/display.cgi?id=1493740391

MMATH08
If you call it an angle bisector, then it will bisect.

maths
check your typing, the second circle contains two y terms and no constant. Is that correct ?

Math geometry
#1. I agree with your first answer of .3535 #2. at least 1 of the 4 marbles drawn is white ---> what you don't want is all non-white. prob(none are white) = (9/12)(8/11)(7/10)(6/9) = 14/55 prob(at least one white) = 1 - 14/55 = 41/55 = .7455 correct to 4 decimals I have...

Math
why would your text write 2 2/4 instead of 2 1/2 ? divide 2 1/2 by 1/4 get rid of those useless mixed fractions .... 5/2 ÷ 1/4 = (5/2)(4/1) = ... or in decimals: 2.5 ÷ (.25) = ...

Math
Got me stumped too, since I don't know what you are talking about. Not familiar with a unit called idk

total surface area would be 2 squares + 4 rectangles = 12x12 + 4(4x12) m^2 = .... Why would you ice the bottom of the cake ?

for e^1 sum(1) = 1 sum(2) = 1 + 1 = 2 sum(3) = 2 + 1/2! = 1/2 = 2.5 sum(4) = 2.5 + 1/3! = 2.5 + 1/6 = 8/3 = 2.666.. sum(5) = 8/3 + 1/4! = 8/3 + 1/24 = 65/24 = 2.70833.. sum(6) = 65/24+1/5! = 65/24+1/120 = 163/60=2.71666.. sum(7) = 163/60+1/6! =163/60+1/720 =1951/720=2.7180555...

Algebra2
in y = a cos (kØ) a is the amplitude, and the period is 2?/k so evaluate the period and state the amplitude of your equation.

Algebra2
correct if your domain for the intersection is 0? Ø ? 2? you should also include ?, 4?/3, 5?/3, and 2?

Math
I must have been thinking about those new type of hexagons that have five sides, duhhh!!

Math
So you need the perimeter. What is 5(52) cm? How many metres is that? (the beauty of the metric system shows up here) multiply number of metres by \$4.10

same question from Bobby/Jules/Alice

math
to be divisible by both 2 and 3, it must be divisible by 6 So the first number past 40 divisible by 6 is 42. Now just add multiples of 6 to 42 that is: 42, 48, 54, ...

STATISTICS
each toss is an independent event, so Prob(99 consecutive heads) = (1/2)^99 or appr 1.5777 x 10^-30 rather slim, I would say

Math
Make a sketch and you will see that you can use Pythagoras x^2 + 1.5^2 = 6^2 carry on

Maths
Tanya ---- x Tshepo ---- 2x+5 jake = 3(2x+5) solve: 3(2x+5) = 45 then sub the value of x into my definitions. What did you get?

discrete math
a) amount at end of 1st year = 8000 + 1600 - 2500 = 7100 amount at end of 2nd year = 7100+1420-2500=6020 amount at end of 3rd year = 6020+1240-2500=4724 amount at end of 4th year = 4724+944.8-2500=3168.80 amount at end of 5th year = 3168.8 +633.76-2500= 1302.56 , which is less...

Math
original number: let the unit digit be x then the tens digit is x+1 since the sum of all 3 digits is 14 the hundreds digit must be 14 - x - (x+1) = 13 - 2x now the actual number, using place holder value, is 100(13-2x) + 10(x+1) + x = 1300 - 200x + 10x + 10 + x = -189x + 1310 ...

math
close, 2 errors! 5% = .05, not .5 why do you set the total to 1200, didn't it say 860 ? make the change, now solve that equation.

math
makes no sense, I think you just wrote something down because I asked you for an equation. you have 3 variables in your first equation, so you will need 3 different equations to solve if a, b, and c are you different investments, then a+b+c = 860 , not 1000. Where did it say ...

math

Math
no, you are just writing stuff down. based on what it said: number of nickels --- x number of dimes---- 2x+1 number of quarters = 25-(x + 2x+1) = 24 - 3x now form a "value" equation: 5x + 10(2x+1) + 25(24-3x) = 410

Math
Ok, your turn. For the first two, I have given you the equation What have you done for these last two? Show me your preliminary steps.

Math
solve 7500+15x = 10000 + 12.5x

Math
let amount invested at 7% be x solve .07x + .1(x-2000) = 820

Elementary Statistics
10 different horses could come in first, that leaves 9 to come in second, and 8 to come in third, so what is 10x9x8 ??

Again, watch those needed brackets, assuming you meant: 4/(2x-3) < 1/(x+4) I see critical values at x = 3/2 and x = -4 try a value x between -4 and 3/2, say x = 0 is 4/(0-3) < 1/(0+4) is -4/3 < 1/4, YES, so -4 < x < 3/2 try a value x < -4 , say x = -5 is 4/(-...

Assuming you meant: f(x)= -1/(x^2-7x+6) = -1/((x-6)(x-1)) vertical asymptotes are caused by the denominator being zero, so x-6 = 0 ----> x = 6 or x-1 = 0 ---> x = 1

Calc
r = 5cscØ r = 5/sinØ we know that y/r = sinØ or r = y/sinØ then y/sinØ = 5/sinØ y = 5 , a horizontal line check: http://www.wolframalpha.com/input/?i=polar+plot+r%3D5cscx