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Questions tagged [ratio]

For questions concerning the ratio of a certain quantity to another.

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Reason for ratio function for comparing predicted and actual values produced by Weighted Moving Average?

I am reading a paper that describes an approach towards detecting abnormal flows within a network. From what I understand, the way they do so is by keeping a list of $n$ most recent metrics and then ...
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2answers
50 views

Example 14, Chapter 1, Higher Algebra by Henry Sinclair.

I stumbled across the question 14 in Higher Algebra by Henry Sinclair and S.R Knight: If $$(a^2 + b^2 + c^2)(x^2 + y^2 + z^2) = (ax + by + cz)^2$$ Show $$x:a=y:b=c:z$$ I started by expanding the ...
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Splitting expenses in a group

There are three friends A,B,C in a shared room. For a period of 30 days, A and B contributed amounts of 137.5 and 79.62 during the whole month whereas C's contribution is 158 during 12 days only. How ...
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2answers
62 views

Does the fact that $\lim\limits_{n\to\infty} |f(n)/f(n-1)| = 1$ imply that $\lim\limits_{n\to\infty} f(n)$ exists?

This question was inspired by another question I asked on this site. For that question, I had thought that if the differences in subsequent evaluations of a function, $f(n)$, defined with a domain of ...
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1answer
848 views

Ratio of Averages vs Average of Ratios

I'm conducting a water savings analysis and I had a couple of questions. If you answer, please provide links to references so I can read up. Thank you! :) Let's say for removing grass from a ...
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1answer
150 views

Determining x:1 from the diameter of the Sun and one of its granules. [closed]

I'm a having trouble solving the following: What is the ratio of the diameter of the Sun to the typical width of a granule on the Sun's surface? Express your final answer in the fully factorised form ...
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21 views

What does a confidence interval tell you about the relationship between two things?

So I have found a 95% confidence interval for the odds ratio of developing cancer with vitamin A intake. My sample odds ratio was 1.1667 with a 95% confidence interval of (0.5394, 2.5227). I am then ...
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1answer
31 views

Homework help : Ratio in Mathematics

So let's say that we have two bottles of orange juice: Orange juice A, and Orange juice B. Orange juice A is 1310ml, and Orange Juice B is 786ml. Now I know that their ratio of A:B is 1310:786. But ...
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1answer
30 views

Re-writing a recurrence relation

Reading a worked example in my notes on recurrence relations, I am told that the following recurrence relation R1 can be rewritten in the form below, R2: This is done by replacing $n$ with ($n - 1$)....
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2answers
29 views

Given two numbers A and B, make them in ration of 3:4 by only adding integer(s) to A or B or to both A and B

I have a set of 2 numbers say 365 and 550, I want to make them in ratio say 3:4 I have the option of adding x and y to 365 and 550, with limitation of x and y should always be integer, both or one can ...
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2answers
146 views

I'm stuck on this angular speed problem :(

So my professor gave us a bunch of problems to review over the weekend and I was able to do most of them with no problem. However this problem really confuses me. It's not being graded, but I would ...
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2answers
22 views

Given a ration x:y, make it to ratio of 1:1 or 3:4 or 4:3 by only adding some values to x or y or both.

This problem is related to programing, for which I am searching an optimal solution. Problem: I have some images in different height to width ratios. I want to make them in ratios of 1:1 or 3:4 or 4:...
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1answer
17 views

Apprently simple proportion question.

There are 5000 buyers of apples, who each on average buy 12 apples a month. There are two types of apple buyers, those that buy red apples, and those that buy green apples. The red apple buyers buy ...
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11 views

Comparing (ordering) rate and sample size

Consider some rate, i.e. fail rate where f is the number of fails and n is the number of attempts. $$failrate = \frac{f}{n}$$ $$failrate = \frac{100}{100} = 1$$ $$failrate = \frac{99}{100} = .99$$ ...
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2answers
37 views

Ratio/scaling (High school)

Have a question from my textbook which is causing some confusion. Q. A map has scale $1:7500$. A town has an area of $37.5~\text{cm}^2$ on the map. What is the real area of the town in $\text{km}^2$...
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1answer
826 views

Ratio Calculation in Linear Programming?

i struggle a bit with ratio and fraction calculations, so im just looking for some explanation for dummies of this one. in linear programming, i have a ratio constraint of 6:5, of product A to ...
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4answers
86 views

Why does 1:2 = 1/2? [closed]

My natural instincts tells me 1:2 = 1/3, because the LHS is 1 part of 3. For example, if something was in the ratio 1:1, I would expect the LHS to be 1/2 of the whole, so why is 1:1 = 1?
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1answer
190 views

If $ab=ba$, $\frac bx = \frac cz$ and $\frac ax = \frac dz$, does that mean that $ac=bd$?

If $$ab=ba, \ \frac bx = \frac cz \quad\text{ and }\quad\frac ax = \frac dz$$ does that mean that $ac=bd $? I tried to prove this but couldn't.
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4answers
57 views

Combining ratios of quantities with different sizes

A friend and I had two different answers to this seeming simple question. It goes as follows: Jar A contains flour and sugar in the ratio 5 : 1. Jar B, which is three times larger than Jar A, ...
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1answer
43 views

ratio divided by zero [closed]

I am trying to display a ratio on a graph and I am having an issue with DIV/0. What I am graphing is capture success vs the ratio of active burrows/inactive burrows. However, the ratio of active/...
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2answers
106 views

How to apply odds ratio to calculate change?

I did a control/treatment experiment and found an of odds ratio $= 2.6 (1.03-6.58)$ mortality in treatment. Thus, for every one death in control there are $2.6$ deaths in treatment. I believe the beta ...
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2answers
39 views

How to simplify the equations below trying to find for ratio test

a) $\frac{ \sin(n) + e^n}{\cos(n) + \pi^n}$ I expanded and got $\sin (n) + e^n/(cos(n) + \pi^n) x \cos (n+1) + \pi^{n+1}/\sin(n+1) + e^{n+1}$? and also how to simplify $(n+1)^e/(n^e)e$ Edit: I ...
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1answer
13 views

Quantity of areas within a larger area broken down by percentages.

I have the following problem to solve. I have a total area of At (Area Total). Example 1000m2 Within that area I want to find out how many 1 bedroom, 2bedroom, and 3bedroom units I can fit. The ...
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80 views

Ratio and Proportions Question

Can someone please answer this with proper explanation. At sahara shopping centre, a person can purchase as much articles at a time as his or her age that is a person of a years age can purchase ...
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1answer
35 views

Does the diagnostic odds ratio for a test increase, decrease or not change if there is a change in the prevalence of a disease?

Does the diagnostic odds ratio of a test change if there is an outbreak of the particular disease in the population? If so, does it increase, decrease or just stay the same?
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32 views

How to bridge operational efficiency ratio between two periods?

I am looking at operational efficiency as a ratio of indirect production costs to gross profit 1 (GP 1 does not include these indirect costs) (Ind Prod/GP). I have been asked to bridge the difference ...
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1answer
46 views

Factoring an equation by 15

The heart muscle is supplied with nutrients and oxygen through the coronary vessels. The blood flow through the coronary vessels by more than a factor of 15 through the deposition of Plaques on the ...
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0answers
141 views

Sorting on non-additive ratios

We are trying to aggregate and sort records by ratios (CTR = clicks/impressions). For some obscure reasons the technology we are using does not allow us to do this. We can group and sort on additive ...
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5answers
46 views

Finding the ratio of $\frac{x}{z}$

$x,y,z \in \mathbb R$ and $x,y,z \neq 0$ $$2x = 5y$$ If $$\frac{y}{3} = \frac{z}{4}$$ Find the ratio of $\frac{x}{z}$ Let me show what I thought We have $$2x = 5y$$ Which means that we ...
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2answers
35 views

Federico's able to finish a job in $15$ days, and Relen's able to finish a job in $30$ days. In how many days can they finish this job together?

Federico's able to finish a job in $15$ days, and Relen's able to finish a job in $30$ days. In how many days can they finish a job if they work together? Let me show what I tried: $$F \implies ...
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1answer
25 views

Get dimensions of inner boxes

I have a box of dimensions $L$,$W$ and $H$. Within the box, I have $Q$ number of other boxes with the same ratio of dimensions. How can I find out what the dimensions of the inner boxes are assuming ...
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3answers
532 views

Ratios and Proportions in Fish Tanks

I was recently studying for a test and got this problem correct. However, I don't think I would be able to answer a similar type of question correct again. The question is the following: A marine ...
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2answers
44 views

In coding the math, how would you calculate how many times the size of one cities population is to another? Like Quebec. pop to Copenhagan pop?

I have a Quebec population : $8,164,361$ And Copenhagen population : $775,033$ How would I be able to determine the how many times the size of one is to another? For example I know for Quebec the ...
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3answers
61 views

Help with this problem involving a triangle

The area of the triangle is 85 square centimetres, the side $AB$ is divided by the point $P$ so that the ratio $BP:AP$ is 1:4 and the side $AC$ is divided by $Q$ so that the ratio $AQ:CQ$ is 2:3. Find ...
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0answers
136 views

% CHANGE IN NEGATIVE BASE

I need to find correct formula to calculate percentage change from a negative base. Assume this is my company financials where Year-$1$ Profit: Negative $80$ Crore Year-$2$ Profit: Negative $...
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1answer
54 views

Classify math problem

Hoping someone can help with following 2 points on question detailed below: 1) Help to clarify what kind of question this is (e.g. ratio problem) so I could plug into google and get meaningful ...
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25 views

Isn't this a ratio variable?

Question: State whether the following variable is an interval or ratio variable? i) Number of car sales per year The solution states that it's an interval variable. But that's wrong. For the variable ...
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1answer
21 views

Calculate the surface if we know the volume and ratio of the edges

If we know that the volume of a box is 5103 cm^3 and that the ratio of the edges is a:b:c=3:7:9, how do you calculate the the surface?
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38 views

Finding out two numbers(ratio and proportion)

There is a question in our book whose answer i am not being able to find out.: Find two numbers such that the mean proportional between them is 28 and the third proportional to them is 224. This is ...
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1answer
748 views

Find the possible values for the common ratio, r.

The sum of the second and third terms of a geometric sequence is 96. The sum to infinity of this sequence is 500. Find the possible values for the common ratio, r.
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1answer
85 views

how to convert $1.91$ (CAD)/kg into dollars/lbs? [closed]

edit: how to convert $1.91$(CAD)/kg into dollar/lbs? I was looking at some grocery pricing and I couldn't figure how to convert back into lbs as some stores will list it in lbs, and others will ...
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1answer
76 views

Logical proof for simple statement,

This seems like a simple question... but I am struggling to find a conclusive proof. (a) If Robinson's squash is double the strength of Johnson's squash, then you need to use double the volume of ...
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2answers
66 views

Why is the sum of three different percent differences not the same as the total percent difference?

To be more specific, I am looking at the numbers $1234, 1345, 1456,$ and $1567$. The percent increase between each number and the number which follows ($1234$ to $1345$, $1345$ to $1456$...) are ...
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39 views

Is there a problem with canonical forms for ratios?

High school maths and ratios at KA show how to solve ratio problems, and when ratios are equivalent - but don't say what the ratio is. I've worked out some canonical forms, and I wondered why ...
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1answer
921 views

Separate impact of change of numerator and denominator on ratio

Please help me with this issue: In period 1, a = 15, b = 10, therefore a/b = 1.5 In period 2, a = 12, b= 12, therefore a/b = 1 As you see, a declined by 20%, and b increased by 20%, as well....
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62 views

Expectation of the ratio between Beta-Prime and Gamma random variables

Given two random variables, $V \sim \beta^{'}(P,PM)$ and $U \sim \Gamma(PM,\zeta)$, where $\beta^{'}$ is the Beta-Prime distribution, $\Gamma$ is the Gamma distribution and $\zeta$ is a real constant ...
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2answers
34 views

Get numbers from ratios

How to get numbers from ratios? For example: The number of students in a school is 17500. The ratio between boys and girls is 4:3. How many boys and girls are there? Not only for this example, but ...
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4answers
4k views

Dividing a rectangle into 4 parts in the ratio 1:2:3:4, with only 2 lines

I have a rectangle made up of 30 identical squares (5 tall and 6 wide). By only drawing two lines on the rectangle, split the rectangle into 4 parts where the areas are in the ratio 1:2:3:4. How ...
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1answer
73 views

How to prove this is a decreasing sequence?

I have this sequence: $\{a_n\} = {\frac {1}{n^{1+\frac {1}{n}}}}$ I tried to take the derivative to show the rate of change is negative for some n but the derivative is not very nice to work with. I ...
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Unexpected number appears

I am working on estimating norms of solutions of the simplified version of the Fokker-Planck equation$$ u_t=\text{div}(b(x)u)+\text{div}(a(x)\nabla u) $$ with $\text{div}\in L^q(\mathbb{R}^d)$ using ...