# Questions tagged [ratio]

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

711 questions
Filter by
Sorted by
Tagged with
74 views

### Dividing Numbers Into Rations

The question is: Suppose $60$ is divided into $3$ parts in the ratio of $1$:$3$:$6$. What is the value of the middle part? I tried to take $60$, divide it into $3$ parts and divide those $3$ parts ...
4k views

### How to calculate a distance with different fraction ratios?

This is the math question for my sixth grader son. The answer is $136$ meters but could not figure it out. Can someone please explain how to solve it. Thank you. Adam first walks $3/8$th of a road. ...
342 views

### Ratios with Ages

The ratio of Sam's age to his son John's age is 8:3. If the sum of their ages is 55 years, what is the age difference between John and his dad in years? So, I divided 55 by 11 and got 5, then ...
384 views

85 views

### Ratio of squares touching edge of circle?

Consider an infinite amount of squares stacked on top of each other where the top left corners are touching the edge of a circle: Call the largest blue square x. How would I find the ratio of square ...
54 views

### Convergence of $\sum_{n=0}^{\infty} \frac{3^{2n}}{(2n)!}$

I need help determining what following series converges to using the ratio test. $$\sum_{n=0}^{\infty} \frac{3^{2n}}{(2n)!}$$ It's the end that really has me confused with what to do with the ...
654 views

### Ratio of sines given, find ratio of cosines?

Is it possible to find $\displaystyle{\cos x \over \cos y}$ if $\displaystyle{\sin x\over \sin y}$ is given? If so, how would one approach this problem? Thank you in advance!
2k views

### How do you do this *without* using a calculator? The ratio of three numbers is $3\frac{1}{3}:4\frac{1}{5}:6\frac{1}{8}$

The ratio between three numbers is: Three and one third: Four and one fifth: Six and one eighth and the sum of the numbers is $4197$. What are the three numbers? Using a calculator, I would just add ...
4k views

### Ratio between two numbers is 6:7 and the difference between them is 10. What are the two numbers?

I know the numbers are $60$ and $70$ but I got that by trial and error. Is there some other more logical way to do this problem?
766 views

### Find common ratio of a geometric sequence given the sum

I feel like I have tried everything with this problem. Here it is: Since this is an infinite sequence, I believe the formula for the sum is found with the equation firstTerm/(1-ratio). I get 6x^7 ...
35 views

### Related rates question.

Two sides of a triangle have lengths $\sqrt{21}~m$ and $\sqrt{7}~m$. The angle between them is increasing at a rate of $\dfrac{2}{\sqrt{3}}~rad/sec$. How fast is the altitude of the triangle ...
58 views

497 views

51 views

### Finding the alternate forms of ratios

This is a super basic algebra question but I can't figure out how you get the alternate form of: $$\frac ab = \frac cd$$ Which is: $$\frac {a+b}b = \frac{c+d}d$$ The process explaining how we ...
778 views

### How to Calculate gear ratio for potentiometer

I am not a mathematician so please bare this in mind. I am designing a computer steering wheel, using real car parts (fitting the steering wheel from a hatchback via gears to a potentiometer which is ...
65 views

### Shared groceries expenses between roommates to be divided as per specific consumption ratio and attendance

My apologies if this question is in the wrong section. Couple of my roommates & I (total 5 people) share the groceries expenses. We record the purchases in an Excel sheet, and also have the ratio ...
124 views

### How many boys, girls, men and women are there?

In a village, there are exactly $10$% more boys than girls; $15$% more women than men; $20$% more children than adults. The population is less than $6000$. Solution: $b = g + 0.1g$--------(i), where ...
71 views

### Expressing a decimal percentage as a ratio

Maths newbie here. How would I express a decimal percentage such as 90.3 as a ratio ("one in...")? I've done a search and the explanations aren't too clear at all. I'm about to enrol on to a ...
80 views

### Selling Corrupt quality of honey with allegation…

I have a problem that uses Allegation concept, I tried it I would like to know If I am Correct..? A Honey seller gets pure honey($1$ Litre ) for $100$ and a sweet oil for $20$ he shall mix honey ...
2k views

### Ratios as Fractions

I’m having trouble understanding how fractions relate to ratios. A ratio like 3:5 isn’t directly related to the fraction 3/5, is it? I see how that ratio could be expressed in terms of the two ...
101 views

### Why does $\tfrac{a}{b} = \tfrac{c}{d} = \tfrac{e}{f} \rightarrow \tfrac{a}{b} = \tfrac{c-e}{d-f}$

Why is it that $$\frac{a}{b} = \frac{c}{d} = \frac{e}{f} \rightarrow \frac{a}{b} = \frac{c-e}{d-f}$$ It is used in the proof of Ceva's theorem. Thank you.
83 views

How is the word ratio defined? I know of two different interpretations of the term ratio, and they are somewhat contradictory. They are: 1) The Reynolds number is the ratio of inertial force to ...
7k views

### Dividing line segments with ratios vs. fractions [closed]

I know that $2:3$ is actually $\frac {2}{3}$. So when you split a line segment by a ratio, you would add $2$ and $3$ to get a fraction of $\frac {2}{5}$ that will be used to solve the problem. I can'...
129 views

### Splitting a segment with a ratio

I came across the homework question that I attempted to do. After looking at the answers, and getting it wrong I didn't understand why. I'm specifically lost at why we would get a fraction of 2/5 at ...
68 views

### Given a value and an arbitrary range, finding equivalent value in other arbitrary range

While strictly related to a programming project of mine, the problem in itself boils down to a math problem, as I am not sure which steps to take to produce the results i need. I have an input value (...
I want to model the inverse relationship between two sets of numbers $A, B$ both in the domain $[-5, 5]$. That is, for the same value $A$ I need a number that decreases linearly as $B$ increases, ...