Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [ratio]

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

In mathematics, a ratio is a relationship between two quantities indicating how many times the first number contains the second. For example, if a bowl of fruit contains eight oranges and six lemons, then the ratio of oranges to lemons is eight to six (that is, $8:6$, which is equivalent to the ratio $4:3$). The numbers compared in a ratio can be any quantities of a comparable kind, such as objects, persons, lengths, or spoonfuls. A ratio is written "$a$ to $b$" or $a:b$, or sometimes expressed arithmetically as a quotient of the two.

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Two people on an escalator past paper

I was going through old past papers and came across this question with only the answer and no explanation. Here is the question: An escalator moves up at a constant rate. Chloe takes 90 steps to walk down the escalator. Jacob takes 45 steps to walk…
Tyrcnex
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What is $x-y$ given $x/y$

If I know $x$ divided by $y,$ how can I work out $x-y$ from that? Suppose $x>y.$ Is this even possible? Thanks in advance.
crvcio
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How to express in ratios.

I have three values which I want to express in ratios. $l = 176.43$ $m = 162.86$ $n = 190$ The ratios must be: $\dfrac{l}{a} = \dfrac{m}{b} = \dfrac{n}{c} $ How to find $a$, $b$ and $c$? I tried so hard, but I couldn't find the values because they…
Isai
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Trapezoid Ratio problem

I am in 6th grade, and I was given this extension for extra practice. The question is: The ratio of one base to the height to the other base of a trapezoid is $2:3:4$. The area of the trapezoid is 117 square cm. Find the length of the bases and the…
Harry Iguana
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How to calculate the range [0,1] of a line section in ratio to the total line length?

(Disclaimer: I am a programmer, not great in maths, so sorry if I don't explain my question in proper mathematical terms. Moreover English is not my first language, which makes it even harder for me to explain. But I will try.) I have a line with a…
Matthias
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Normalise rest of list

I have an list of fractions as such: sum(3/10, 1/2, 1/5) = 1 and I multiply some element (the second in this case) by some known factor (1/2 here): sum(3/10, 1/4, 1/5) != 1 So the answer would be: sum(????, 1/4, ???) == 1, where arr[0] and arr[2]…
DaraJ
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Ratio & Proportion - Splitting the ratio

A picture is made up of just two colours, red and green. They are used in the ratio 4:3. In the picture, if the ratio of red and green in the lower half of the picture is 2:3, then what is the ratio of red and green in the upper half? Solution which…
Krishna M
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Is my math correct for scaling something in 3 dimensions?

If object $A$ weighs $10$ grams and is, for example, a $1 m^3$ cube, and object $B$ is of the same density but $2$ meters long in every direction rather than $1$ meter long, that would make it an $8 m^3$ cube. I know this much. But since we're…
Sam Hill
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How to find the oil concentration of the resulting mixture?

Question Two cans of oil cost Rs. $75$/litre and Rs. $60$/litre for oils of $80\%$ and $40\%$ concentration. When they are mixed in a certain proportion, the resulting can of oil costs Rs. $56.25$. Find the oil concentration of the resulting…
tarun jha
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Conversion between in$^2$oz$^{-1}$ and cm$^2$g$^{-1}$?

I want to convert $~16~$in$^2$oz$^{-1}$ into cm$^2$ and grams. This is my attempt: I just want to check that my answer is correct, as my book says it should be $~3.686~$cm$^2$g$^{-1}$, but I got $~3.641~$. I’m pretty sure this difference is due to…
Jamminermit
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If $A\propto BC,$ then $A\propto B$?

Let $A,B,C$ be variables. If $A$ is directly proportional to $BC,$ can we always say that $A$ is directly proportional to $B$ and that $A$ is directly proportional to $C\,?$
Bhargav Nadig
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Ratio question help: are my answers correct?

From the question given below, I am trying to, firstly, find the proportion of iPhone users from the information provided in the Business Scenario. Secondly, I am trying to find the share of Android logins given the updated information. For these…
Klaus
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Ratios With Three Factors?

How do I compare a different objects with three rates? For instance, if I were to compare the price of apartments I would look at the price per square foot, a rate with two factors. But if I wanted to add a third value, let's say distance from town,…
Ben Bertram
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How do I calculate combining two ratios to create a new third ratio

Can someone provide me with a formula that directs me in combining two known ratios to create a new third ratio? Solution 1 contains 43mg ingredient A, and 3.7mg ingredient B for a ratio of about 12:1 Solution 2 contains 0.69mg ingredient A, and…
Tom
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Converting between different scales

I have a scale which goes from 0 to 100. Given a number on that scale (say 33) I want to find the corresponding value on another scale which goes from 25 to 100 (in this case I think the answer is 50). Any ideas how I should go about working out the…
richwol
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