Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [problem-solving]

Use this tag when you want to determine the thinking that is needed to solve a certain type of problem, as opposed to looking for a specific answer to a question.

Use this tag when you want to determine the thinking that is needed to solve a certain type of problem, as opposed to looking for a specific answer to a question.

4495 questions
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A question about profit and loss

A shopkeeper allows a discount of 20% on the marked price but charges 5% sales tax on the marked price and 5% service tax on the discounted price. If the customer pays Rs. 2670 as price including tax, then what is the marked price on the item?
user605287
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how to solve this profit and loss problem

Xavier buys an apple from Yahoo for Rs.5 and sells it to Zoe for Rs.10. He later buys the apple back from Zoe for Rs.12 and sells back to Yahoo for Rs.15. What is his profit over venture?
user605287
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Related rates ladder problem, what is wrong with my algebraic solution?

So while reading the solution (which uses implicit differentiation) of the following related rates ladder problem I thought about the algebraic way of solving it, but it gives wrong result so I want to know what is wrong with it. The problem is this…
Юрій Ярош
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Formula for a "weighted" scale?

I'm trying to find the formula (or even just the area of math) that I need to achieve the following concept. I need a scale (X) from 0-100, that wraps around another scale (Y) where the Y values are "weighted" and become more and more compressed the…
Andrew
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Formula for Contractor's Hourly Rate

Assume the number of work hours per year is 12 (months) x 4 (weeks per month -- for the purposes of this problem, assume 4 weeks per month) x 40 (hours per week) = 1920 hours per year. Furthermore, assume a goal of incentivizing companies to hire a…
MathNewbie
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Need help explaining method of calculation for a school question for my $10$ year old

A family friend sent us an example question that said a child starting secondary / high school would have in their first year. We tried showing it to my 10 year old who was unable to do it, after having a look myself I don't know either. The…
GrandMasterFlush
  • 103
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Does a solution exist for this problem?

Suppose let's say I know $\tau > 0$ and $\rho > 0$. I am looking for a non-trivial solution $\eta, \delta, \omega$ all constants (independent of $t$) and greater than zero, such that: $$ \tau e^{-\rho t} = \eta +\delta e^{-{\omega t}}. $$ Please…
user2167741
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The egg drop problem where the aim is to minimise the time taken

In the standard egg drop problem you are in front of a 100-storey building and by dropping eggs from $k$ different floors you plan to find the lowest floor from which you can drop an egg without breaking it. Your task is to find the smallest $k$…
user583837
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Most efficient method of reaching (a, b) = (0, 0) given you can only multiply a or b by 2 or add to both.

Question: You have two numbers (a, b). At each step you can either multiply just one number by 2, or add any number (negative included) to both. What is the minimum number of steps to get from (a, b) to (0, 0)? Justify. I’ve given this question a…
MKY6
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Is it possible to evaluate any unknown in an equation?

E.g., I have this function $P = e^{-x} \frac{x^k}{k!}$ and I can't figure out how to evaluate $x$ If it's possible, please show me how. And if it's possible, is it possible with any equation?
Hrisip
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How to solve tractrix equation for x?

Tractrix curve is defined by the following equation: $y= asech^{-1}(x/a)-sqrt(a^2-x^2)$ where a is a constant. I would like to apply this equation for an algorithm where y is a known value. Is it possible to solve it for x?
Roman
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How far could the plane travel before it made its return?

A fighter plane had enough fuel to last a 6-hour flight. The speed of the wind and the speed of the plane made up a total of 1500km/h when the plane was flying in the direction of the wind during its mission. On its return trip, the total speed was…
Peaceyou
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Solving an equation in a special form

I want to deduce the special form of $$w^2 = \frac{k_z^2}{2a^2}\left[b + \sqrt{b^2 - 4a^2T}\right]$$ from the equation $$ \left(1+ \frac{k_z}{wk_x}\right){k_x}^2 = \left(T -\frac{ w^2a^2}{k_z^2}\right)\left(\frac{k_z^2}{w^2} - 1\right)$$ Also it is…
user533186
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Geometry problem with circumference

Could someone explain me how to demonstrate the following problem ? (I had to translate it so sorry for any grammatical mistakes as english isn't my first language) From a point C outside a circumference draw a tangent CA and a secant that…
Luca Gervasi
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Mathematical approach exercise

I have this statement: A father have $x$ years old, and his son $y$ years old. ¿Within how many years the age of father will be four times the age of his son? $x =$ Father years, $y =$ Son years $x - y =$ Year of the birth of his son. The father…
ESCM
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