Questions tagged [word-problem]
A word problem is an exercise with its main challenge being in translation from words to mathematical concepts and language including symbols and formulas. This tag is not about the unrelated topic in group theory.
1,118
questions
5
votes
1answer
42 views
Profit/Loss percentage question
Tom buys $18$ lobsters at the same cost. He sells $16$ lobsters at a $60\%$ profit. Each of the remaining lobsters are sold at the same loss. It is given that the overall percentage profit is $50\%$. ...
2
votes
1answer
39 views
The probability of recovering from a disease
It is known that the probability of recovering from a disease is $0.23$. In a community of 6 people with this disease, what is the probability that at least $3$ people will survive?
Hello guys, today ...
0
votes
0answers
22 views
Formula for water tank level with complex rules? [closed]
You have a water tank with capacity C. At time t=0, the water tank is full. n people drink ...
1
vote
2answers
30 views
Combinations question involving committee and restrictions
In how many ways can a committee of three women and four girls be chosen from seven women and six girls so that if the eldest woman is serving on the committee then the youngest girl is not?
The ...
-1
votes
0answers
17 views
How do you solve this compounded interest problem? [closed]
Penelope is starting a college fund fo her daughter, age 10, and assumes the cost for her first year of college at 18, will be $24500. She finds an account that pays 6.85% APR, compounded quarterly. ...
0
votes
2answers
38 views
What would the probability out of these 28 marbles be? [closed]
A bag contains 28 marbles total, with 9 red marbles, 9 white marbles, and 10 blue marbles.
You draw 3 marbles out at random, without replacement. What is the probability that all 3 are red?
P(all 3 ...
1
vote
4answers
41 views
Which jar contains a higher percentage of the color it started with?
This is a problem from Brilliant.org
Two jars each contain 1000 candies. One jar contains all green candies
and the other contains all red candies. Take 200 green candies and
move them to the red jar....
0
votes
1answer
18 views
differential equations, exponential population growth
If p is population and t is time. Does that mean that when you do dp/dt = 0 you can find the maximum and minimum population
1
vote
1answer
47 views
Help understanding Calculus Word Problem [closed]
I have been working on this problem for about 4 hours now, and still can't figure it out. Can anyone help me?
A hiker is returning to a campsite that is 2 miles east and 7 miles south from their ...
-5
votes
0answers
23 views
Digit word problem [closed]
The unit's digit is twice less than the ten's digit. Find the number, if it's 18 more than the reversed number.
Let x be the units digit
-5
votes
0answers
25 views
The sum of the digits of a two-digit number is 15. The units digit is one less than the tens digit. Find the number. Let $x$ be the tens digit. [closed]
The sum of the digits of a two-digit number is 15. The units digit is one less than the tens digit. Find the number. Let $x$ be the tens digit.
1
vote
0answers
47 views
What are non-numerical variables such as “Heads” and “Tails” officially called?
Is there a mathematical terminology for non-numerical variable such as
Head Tail (referring to a coin flip) or Rock Paper Scissors or Up/Down ?
For example, I want to say that my set $\mathcal{S} $ ...
0
votes
2answers
32 views
Word problem about exponential equation
I have the following exponential equation problem:
A company launches a new product and has the following function describing the daily units of that product sold:
$$
f_{k}(t)=k(t-15)e^{-0.001t}+15k
$...
0
votes
0answers
29 views
Looking for word problem books
I am looking for Grade 6 - 12 math books with word problems least 1/4 page long or more. Long time ago I once saw one such word problem practice book for grades 6 - 8, but I can't remember the title ...
0
votes
0answers
19 views
A “math word” problem - “catch per hour for each kilometer”
Thank you for your time. Please take a look at an LSAT sentence below:
THE CPUE, i.e. "catch per unit effort," for any species of shark is
the number of those sharks that commercial fishing ...
5
votes
3answers
118 views
False proof that $\frac{13}{6}=0$
At start, the length of a line segment is $a_0=0$. When $3$ hours have elapsed since start, its length is $a_3$. When $1$ hour has elapsed since start, its length increased by $\frac{a_3}{2}$ with ...
1
vote
3answers
62 views
How to find the elapsed time for one candle to be consumed when it is thicker by three units with respect of another?
The problem is as follows:
Assume that you have two candles. One is the triple of diameter of the other. Both of these candles are of the same quality and equal in length. Then they are lighted ...
4
votes
3answers
74 views
Which value should be in the numerator? How to think about fractions? **Updated**
If I have a word problem with a fraction, how should I know which value should be in the numerator?
Say I have the following problem:
"You stand 180 meters away from a radio tower. One wavelength ...
2
votes
1answer
98 views
Seeking an example of a group with finite presentation for which the Word Problem is not solvable
In the book Geometric Group Theory of Clara Loh, it is proven that the Word Problem is solvable for hyperbolic groups. It is also stated that the Word Problem is not solvable in all finitely presented ...
0
votes
1answer
45 views
Algebra word problem : magician
A magician is playing mind tricks with the audience. He asks one member of the crowd to think of two numbers, write them on pieces of paper and throw them into his hat. Meanwhile, the magician also ...
1
vote
0answers
24 views
Basic algebra word problem
Alaska is a logician who also likes to impress people with his use of simple logic to do “magic tricks”. He is practicing his next big trick. He asks his friend to think of two numbers, write them on ...
2
votes
1answer
41 views
Basic word problem
Friends Matt and Gary are planning to study together. Matt buys some pencils and erasers. Gary spends the same amount of money to buy thrice as many pencils and five less erasers. Now they are set for ...
0
votes
3answers
39 views
Given $\cotθ = 1$ and angle θ lies in the third quadrant, determine the value of $\secθ$ and $\cscθ$
Recently learned about the reciprocal trig ratios and I'm still don't fully understand them. Wondering if I can get a little help not only with this specific question but the calculating reciprocal ...
0
votes
1answer
30 views
Time and Work : Alternating Workers
Two taps $A$ and $B$ can fill a tank in $20$ minutes and $30$ minutes respectively. An outlet pipe $C$ can empty the full tank in $15$ minutes. $A$,$B$ and $C$ are opened alternatively each for $1$ ...
0
votes
1answer
29 views
How to get the list price of a tv when a discount has been made?
The problem is as follows:
A seller has made a discount of a $15\%$ from the list price of a tv.
Then he makes another discount of 20 usd and still gets a profit of 12
usd. If the cost of that tv was ...
0
votes
3answers
42 views
What is the price of the apples and how many were they brought?
The problem is as follows:
The cook said "I paid $12$ usd for the apples I bought" and they gave
me two apples because I claimed that the apples were too small, that
made me pay one dollar ...
-4
votes
1answer
46 views
Find the number of persons who will go to the party [duplicate]
John emailed 128 people to invite them to the restaurant's inauguration party. He asked these guests to send the email to 5 others in exchange for participation in a lottery where a free meal for two ...
1
vote
1answer
31 views
How to find the remaining percentage of lemon juice?
The problem is as follows:
Assume that you have three mugs. Each mug has a capacity of
$1\textrm{liter}$. The first mug is full and it has $60\%$ of orange
juice and $40\%$ of water. The second mug ...
0
votes
0answers
22 views
Exponential Growth and Decay Problem
The human ear can withstand 85 dB for 8 hours before permanent hearing damage occurs. Given that the exposure time is halved for every 3 dB increased over 85 dB, find the safe exposure time for:
I) ...
0
votes
2answers
32 views
How to find the time for a treatment when counting the difference of pills taken?
The problem is as follows:
Louis took three and a half type $A$ pills every twelve hours and a
half type $B$ pills every $6$ hours. He did this until the difference
in the number of pills taken was $...
1
vote
1answer
30 views
How to find the elapsed time for a medication when two people have to met a certain dose?
The problem is as follows:
In a children's hospital in Tokyo a doctor has prescribed to two kids
a medication to alleviate their sore throat infection. According to
this Hiroto and Midori must begin ...
0
votes
0answers
34 views
How to find the number of kids who got a gift from their godparent?
The problem is as follows:
Mr. Sidney is the owner of chocolate factory. It happens that he's
also the sponsor of a kindergarden called Carousel nearby. Recently he
has decided to give presents to ...
-1
votes
1answer
20 views
How to get the minimum cost for a set of two oranges?
The problem is as follows:
Jenny goes to the groceries supermarket and she notices the following;
In the fruit section, for one kilogram of oranges, six small or four
large ones are obtained, in ...
-1
votes
1answer
35 views
Escalator word problem [closed]
I've been trying to crack this, but I've just given up at this point. The problem sounds like this:
The escalator is always going down. When a boy runs up it, he counts 150 steps, and when he runs ...
0
votes
3answers
63 views
Solving a cubic equation on an interval
$d(t)=-3t^3+45t^2+600t$ where $0\leq t \leq 10$
What is the value of $t$ if $d(t) = 3750$?
Practice question from my textbook I'm having a little trouble with for some reason. Would like to have the ...
1
vote
0answers
13 views
Composite function rates of change
The area of a circle is $A(r)=\pi r^2$. The radius of a circular oil spill is increasing at a speed of $1/2$ m per second.
Express the radius as a function of time.
Find the composite function $A(t)$...
0
votes
1answer
37 views
Trigonometry - word problem
The Question
The machine tool diagram shows a symmetric die punch.
In this view, the rounded tip is part of a circle of radius r, and the slanted
sides are tangent to that circle and form an angle of ...
1
vote
1answer
32 views
How to find the least number of chips to get right each color?
The problem is as follows:
Claire has as porcelain jar (it is not transparent) with 141 plastic
chips inside. They have the same weight and size. But they have
different colors, some are red, others ...
6
votes
2answers
49 views
Trigonometry - worm thread related word problem
The Question
The machine tool diagram shows a symmetric worm
thread, in which a circular roller of diameter 1.5 inches sits.
Find the amount d that the top of the roller rises above the
top of the ...
0
votes
2answers
38 views
Rotation of a wheel in the positive direction and clockwise?
The Question
I’m riding my bike at a constant speed of 20 miles per hour on flat
land when i ride over a dot of fresh yellow paint, thereby getting a
yellow spot on my front wheel, which is 2 feet in ...
1
vote
2answers
28 views
How to find the number of trousers sold by a merchant on a specific day of the month?
The problem is as follows:
The owner of a bazaar in Daegu obtained for the sale of pants of the
same price, $6804$ usd in September, $10800$ usd in October and $7938$
usd in December. If the price of ...
2
votes
5answers
45 views
A more logical approach to a word problem
I was taught in high school algebra to translate word problems into algebraic expressions. So when I encountered this problem I tried to reason out an algebra formula for it
For every dollar Ben ...
0
votes
1answer
39 views
How to find the number of tables to accomodate men and women?
The problem is as follows:
On the occasion of Bob's grand opening of his new restaurant he
noticed that he only has $10$ VIP tables. These will be used to
accomodate $48$ men and $36$ women. He wants ...
0
votes
2answers
44 views
Bacteria population growth
The population of bacteria triples each day on a petri dish. If it takes 20 days for the population of bacteria to fill the entire dish, how many days will it take bacteria to fill half of the petri ...
0
votes
1answer
39 views
Calculus - Calculate Work done to lift water out of tank
I need help setting up the integral so that I can calculate the work done. I've tried it many times and have referred to Youtube, slader, the textbook, and also this site, but I still don't get how to ...
-1
votes
1answer
32 views
What is the greatest number of baskets that Mikayla can make if she wants to put the same amount in each? [closed]
She had 60 apples and 72 pears and we want to split them equally into baskets.
I'm kinda confused because I'm in third grade and I'm learning this.
0
votes
1answer
27 views
Finding the change ratio from given question
First post here.
So, to further explain my question, I want to know what to look for when trying to determine what value changes with respect to the other value; basically which value is $x$, and ...
1
vote
1answer
52 views
Formulating a problem as a linear program [closed]
I have the following problem:
I want to sell five computers. Denote them by $1, 2, 3, 4, 5$. I am allowed to take offers for subsets of the five computers. Three buyers, $A$, $B$, and $C$, want to ...
0
votes
1answer
24 views
Insurance Base Rate question
There is an FKK Indemnity that insures automobile liability risk for data scientists. There are two rating classes, Honda and Toyota. The Base Rate for Honda is 300 for 6 months at basic limit of 25,...
0
votes
0answers
16 views
Group presentation seen as a rewriting system
$\newcommand{\inv}[1]{#1^{-1}}$
(I am not very familiar with rewriting systems, and so it is likely that some of my constructions are either trivial, not needed or already standard assumptions)
Let $G ...
