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Questions tagged [percentages]

A percentage is a number or ratio expressed as a fraction of $100$. It is often denoted using the percent sign, "$\%$", or the abbreviation "$\mathrm{pct}$." -Wikipedia. Percentages are used when describing portions or proportional changes.

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Number of oranges left [on hold]

At a fruit stall, $40\%$ of the fruits were oranges and the rest were apples. After some oranges were sold, the number of oranges became $20\%$ of the total number of fruits remaining. There were $120$...
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Percentage with negative numbers

I have several competitors in an economic market, each one with a score of a strength indicator. Scores can vary in [-inf,inf]. For a subset of competitors, I need to calculate their relative ...
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Calculate the reverse percentage if total is unknown

Lets say, I'll get 100.000 USD in 30 days, but I need most of the money now. I find a (possibly weird) bank who offers me 1.25% interest for these 30 days, which is $1250. So they pay me 98.750 USD ...
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Total fish in a tank

A tank had 20 clownfish and angelfish. 4 clownfish were sold and some angelfish were added to the tank such that the number of angelfish increased by 50%. After that, there were 18 fish in the tank ...
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Number of pupils in the school choir

The number of pupils in the school choir increased by 12% to 56(it seems like this is not a percent). How many pupils were there in the choir at first? My question is, how do I create an algebraic ...
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Hypergeometric Distribution & Probability of selecting without replacement & n Percentage

I will ask my question through an example. There is 100 man in N. 20 man "have card", 80 man "does not have card". If i randomly pick 50 man, what is the percentage of "man with cards" in this 50 ...
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How to get the reverse percentage (not amount of reverse percentage)?

if 100 x 1.17 (17%) = 117, how can I know how many % I have to deduct 117 to get 100? Obviously, this is no more 17%. The same can be applied if 100 - 10% = 90. Then how many % I have to add to 90 ...
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Average percentage of a subcategory

I have a list of numbers of unknown length whose average is x (in fact its 68, but that's not relevant). Some subcategory of that list has an average of y (71) - I don't know how many items are in ...
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Stumped please help!

Is there an easy formula to calculate the percent deifference between two numbers that equal a whole? For example if I want to know what two numbers are 33% in difference but equal 3,200. So I know ...
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1answer
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Pizza Problem, percents

A medium size pizza at Ristorante Porcupine is 10 inches in diameter. A large pizza is 21 inches in diameter. What percent larger is the area of a large pizza? Express your answer to the nearest ...
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Wally Bought A Dog

Wally bought a dog. There was a $25\%$ discount because it was a sale day, a $10\%$ further discount off of the result because it was a big dog, and a $5\%$ further discount off of that result because ...
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Straight forward question about fraction — re-arrange fractions and percentage

Let's say I want to interview $123$ students (years $1$ to $6$) and I'll find $40\%$ of them in the first year of the medical school, and $10\%$ of them in the second year, $20\%$ in the third year ...
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Basic maths: Interview question getting proportion from averages

It's probably simple but I was given this question in a video interview recently and I spent ages coming up with two different answers. (please let me know if this is the wrong place for this, I'm ...
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How do I create a commission structure (%) that goes up when markup (another %) goes down?

I am trying to create a formula in Google Sheets. I have two variables. A sales markup, for a retail outlet, and a sales commission for a salesperson. Ideally, I would like the relationships between ...
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1answer
25 views

What is the correct terminology to be used when talking about % changes?

Throughout my life, I read a "60% increase in x" as $ 60\% * x + x $. For example, if a question asked, "If the initial value of Gold was $39, 162 and if it increased by 50%, what is the price now?", ...
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19 views

Percentage of Outcome

I have a vendor bill which I need to pay. It is for $800. The government mandates that before I pay the bill I deduct 2.73% from the paid amount of this bill because the vendor is non compliant. How ...
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1answer
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How to add percentage value by multiplication?

I'm studying the APL language and doing the exercises here: One of the questions is: b) Add 15% to each number in the list 14 5 78 145. I tried this: ...
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Percentages on population [closed]

The population of london is 12,60000. Of this 2/3rd are men and they are to marry women of London only. If 40% of men were married, find the % of unmarried women?
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Percentages on votes [closed]

In an election 60% of votes cast their votes. There are 80,500 people in the area. In a contest between Mandy and Shah, Mandy won the elections by 1300 votes more than Shah. By what % of votes cast ...
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How to calculate percentage distribution after changing the set

My first language is not English so I apologize if I use incorrect terminology. EDIT: There is a better example with pictures at the end of the post For the sake of argument: I have a table of 10 ...
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1answer
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Need help in finding my mistake in one fraction/percentage word problem

Question : Jennifer has 40% more stamps than Peter. However, if she gives 45 of her stamps to Peter, then Peter will have 10% more stamps than Jennifer. How many stamps did Jennifer begin with ? ...
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2answers
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Probability with 3 dice

My friends and I play a dice game with three dice. One of the winning combinations is 4-5-6. Which can be made with any of the dice as long as the sequence comes via any of the three dice. I ...
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1answer
35 views

Convert lowest number to highest score and highest number to lowest score

I apologise if this is something very basic, but I really struggle with maths! I am programming a system where the shorter the distance between two locations the higher the score will be out of say a ...
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1answer
14 views

Percentage of percentage to get a normalized trend

I am not really good at math and just would like to understand whether what I make makes sense: I have two different teams who estimate their effort while working on two identical projects. Team A ...
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5answers
31 views

Which is right way to calculate percentage?

A student gets the following marks. 50 out of 100 120 out of 150 30 out of 50 In first method : I calculate the percentage as (sum of obtained marks) / (Total marks) * 100. Hence [(50 + 120 +...
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Percentage of fish with stripes

The question I’m trying to solve: The percentage of fishes in a tank with stripes is 45%. The fish have either red or blue stripes, or both. Of the fishes with stripes, 70% have red stripes and 50% ...
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1answer
28 views

What is the correct way of calculating the average percentage in this scenario?

Assume that there two people working in a call centre: PersonA and PersonB. They are both waiting for calls in separate locations. I want to calculate the average amount of time spent waiting ...
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1answer
82 views

How do I find the minimum percentage of students liking at least $3$ of the sports?

I have done every method I know of. The teacher said it took him 2 weeks. I am completely lost. In a middle school, $79\%$ of the students like basketball, $64\%$ like volleyball, $49\%$ like ...
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1answer
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Why my arithmetic approach in a particular % question does not work

Note: Since i could not copy the text of the question i had to attach it as images. I have 1 question in my book as below Data Question The correct answer to this question is 108.7% based on the ...
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1answer
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Can you calculate an average of percent change of knowledge questions?

I have a dataset that includes 3 distinct knowledge questions where pre-test and post-test answers were captured. % change was calculated for the correct answer choice in the 3 questions. Is it ...
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2answers
29 views

Intersection of percentages

I have a problem with the following details: 50% total = comfortable 75% total = without 25% total = with 70% of *with* are comfortable What percentage of ...
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1answer
75 views

Intuitively, why is X% of Y = Y% of X?

I didn't spot this trick until I read this: LPT: X percent of Y is equal to Y percent of X. I know that multiplication is commutative; obviously, $\dfrac{X}{100}Y= X\dfrac{Y}{100}$. But this ...
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1answer
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Figuring out Percent of decimals

This may seem really juvenile but I honestly am struggling. I remember in school being taught this: 1% = X / 100 Then to figure out any percent times 1% by Y. ...
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Quantitative aptitude-profit and loss

A merchant earns 25% profit in general Once his 25% consigment was abducted forever by some goondas. Trying to compensate his loss he sold the rest amount by increasing his selling price by 20%.What ...
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1answer
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How to calculate percentage drop

I have a business problem which requires calculating drop in percentage across different stages in a survey. Unfortunately, I can't give out the actual business case due to confidentiality reasons, so ...
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1answer
191 views

Rob spent 25% more time on his research project than he had planned. He spent an extra h hours on the project.Khan Academy

The explanation says that he planned to spend $($h$/$25%$)$(100%) hours on the research project. How did they come up with the expression and i don't understand why the h is divided by the 25%. I do ...
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1answer
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If I generate a number from 1 to 100, there is an equal chance to hit any number, but how do I get an exact % chance

I am creating a game, and I feel like I am going about the random generation of a number wrong. I have a set plan that the user has a 5% chance to win prize A, and a 10% chance to win prize B. 40% to ...
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3answers
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An “everyday math” problem that I need help in understanding

I understand that you are supposed to use reverse percentages or maybe apply the Total amount payable formula, but I just don't know how. I've been at it for two hours now and I can't seem to figure ...
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How to measure the rate of decrease or increase of a particular stock in a specific time period

I need to measure the drop or increase of the value of a stock within a specific time frame. For example given a company XYZ, I need a formula to calculate the percentage change in value for stock XYZ ...
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1answer
271 views

What is the difference between $x\times 0.8$ and $x \div 1.2 ? $ [closed]

I came across this problem in a Khan Academy course: There are 20% percent more goblins than wizards in a magic club. There are 120 goblins in the magic club. To solve this problem I tried: $...
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4answers
160 views

A team won 80% of the games it played 5 more games of which it won 3 and lost 2. Its loss percentage changed to 25% how many games it play overall? [closed]

A team won 80% of the games it played 5 more games of which it won 3 and lost 2. Its loss percentage changed to 25% how many games it play overall ? What does this question mean? I am not able to ...
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3answers
27 views

Calculate improvement percentage based on time spent

I am doing a task that it takes 2 hours. After some changes the same task takes 10 minutes. What formula I can use to calculate the improvement percentage between these 2 values?
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6answers
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Misunderstanding of percentage increase [duplicate]

If something increase $50$ to $200$, I know that it is $400\%$ increment using common sense. I can get this using $\dfrac{200}{50}\times 100\% = 400\%$. If something increase $50$ to $52$, I know ...
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1answer
18 views

House annual price

Based on the question above may I know whats the answer and how to get the answer. I'm confused whether after 2 years is the 2nd year or the 3rd year. Thanks.
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2answers
38 views

Calculate the total cost of a loan with variable interest rate

I would like to compare mortgages on a $100,000 loan to see which is most economical. Option 1 5 years at $1.89\%$ then 5 years at $3.78\%$ Option 2 10 years at $2.49\%$ Is it simply a matter of ...
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1answer
36 views

Finding the simple formula for like vs dislike ratio percentage

I have a like button and a dislike button. I want to quickly display in a percentage format how much people like it, -100% being everyone dislikes and 100% being everyone likes. What would be the ...
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1answer
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Given we want to charge 0.5% of the total but we don't know what the total is, just what we paid.

This is very basic but struggling with coming up with an answer and would appreciate the help. Given an amount + fee (0.25% on amount), how can I work out what the remainder of the fee is so that ...
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2answers
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Calculate packet loss with random transmission times and TTL

If I have random lag times from a=0.1 to b=0.3 and a time to live (TTL) of x=0.25, what ...
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2answers
31 views

How to know the variable percentage between two numbers? [closed]

1024 -----> 100% 940 -----> x% 800 -----> 0% So (x) what percentage is it? I appreciate the help!