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#26 Re: Help Me ! » Venn Diagram Mathematics » 2023-11-22 10:31:46
Ok. Here's a start:
https://i.imgur.com/SrBFYZG.gif
The total in the H circle is 20. Don't write it inside the circle as the circle has 4 regions and they total 20 when you add up all four.
The overlap of all three (ie. those who do all three sports) is x.
We know that H and C is 7. H and C overlap in 2 regions that I'm calling H+C+F and H+C+F' (hockey, cricket but not football)
As H+C+F is x, that means that H+C+F' = 7-x
You have the information to similarly do H+C'+F (hockey and football but not cricket) and H'+C+F.
Finally you can do H+C'+F' (just hockey on its own) so that the four regions add up to 20 and the others similarly.
Take 18 from 50 to get the total of the 7 regions within the circles and make an eqaution using all those x expressions and solve for x. Then you can write in all the numbers for the regions. Check consistency with the initial information.
Bob
Thank you for the venn diagram photo but I still can't come up with the equation. What is the correct equation to solve for x?
#27 Re: Help Me ! » Sum of All Even Integers » 2023-11-22 10:23:24
I meant times by 2. Every even number is double an integer eg 100 = 2 times 50
Sometimes I type x for multiply.
Bob
Sorry Bob but I'm still a bit confused. Can you start this one for me?
#28 Re: Help Me ! » Is Compound interest sometimes effectively the same as simple interest » 2023-11-21 05:39:48
I’ve come across questions recently that go something as follows;
Tom invests £2000 for 3 years.
For the first year he gets 3% compound interest...
Then for the next two years he gets x% compound interest. Etc.
I’ve been managing to get the correct answer, but the idea of someone receiving compound interest ‘for the first year’ seems strange to me.
Compound interest by it’s definition seems to me to only make sense if someone receives it for 2 or more years. If they are said to get it for ‘the first year,’ i.e, for 1 year, how does this differ from them getting simple interest for 1 year?
£2000. Compound interest. 3%. 1 year. Savings at the end of 1 year = £2060
£2000. Simple interest. 3%. 1 year. Savings at the end of 1 year = £2060Is that correct?
Interest, simple interest, compound interest are three different worlds. Learn the definition of each one before solving applications in this regard.
#29 Re: Help Me ! » Rearranging formulae » 2023-11-21 05:36:08
Make t the subject of the formula
p=(3-2t)/(4+t)
The left hand side was given in the traditional fraction form, with numerator on top of denominator; this is just the same, yeah, with the slash?
Here's my attempt;
Step 1
Mult.both sides by 4+t;
p(4+t)=3-2t
Step 2
Expand brackets;
4p+pt=3-2t
Step 3
Sub.4p from both sides;
pt=3-2t-4p
Step 4
Add 2t to both sides;
pt+2t=3-4p
Step 5
Factorise left side;
t(p+2)=3-4p
Step 6
Divide both sides by (p+2);
t=3-4p/p+2
Are you seeking help or teaching a mini lesson?
#30 Re: Help Me ! » Mathematical geography - homework » 2023-11-21 05:34:41
Good morning. I would like to ask you if you could help me with my homework. i have some exercices what I must calculate on homework in school. But I dont know how to start. Please is there some possibility to find solution of my school homework? I try to calculate it still.
1. What is the length of the 0°W parallel in a Lambert azimuth display at a scale of 1:150,000,000? Round the result to whole millimeters.
2. What is the length of the part of the prime meridian in the region between the parallels of 80°N and 10°N? Calculate the result for the world map in orthographic projection at a scale of 1:120,000,000 and round to whole millimeters.
3. What is the latitude of a point that has Cartesian coordinates X: 50 mm and Y: 15 mm on a map in an orthographic projection at a scale of 1 : 90,000,000? The North Pole lies at the origin of the Cartesian coordinate system. Round the result to whole degrees and enter only the numerical value (without marking NW, SW, etc.).
4. How much more mm is the distance between the North Pole and the parallel of 10° N on the map in the Postel view compared to the map in the Lambert azimuth view? Both maps are on a scale of 1:90,000,000. Round the result to three decimal places.
5. What is the length of the part of the Prime Meridian in the area between the parallels of 50°N and 20°S? Calculate the result for a world map in the Mercator view at a scale of 1:80,000,000 and round to whole millimeters.
6. On the world map in Behrmann's display at a scale of 1 : 120,000,000, the area between the Arctic Circle, the Tropic of Capricorn, the meridian of 70° W and the meridian of 50° E is marked. What is the area of this area drawn on the map? Enter the result in mm² and round it to a whole number.
7. What is the latitude of a point drawn on a map of the Northern Hemisphere at a distance of 30 mm from the equator (the distance is measured along the local meridian)? The map is made in Marin's view at a scale of 1 : 65,000,000. Round the result to degrees and enter only the numerical value (without indicating N.W.W.).
8. The American state of Colorado is marked in color on the map in Lambert's cone display at a scale of 1:10,000,000. What is the area of the colored area on the map? Calculate based on the meridians and parallels delimiting the given territory (it has the shape of a rectangle). The latitude of the undistorted parallel is 25° N. W. Give the result in mm².
9. Calculate the length of the segment drawn on the map connecting Prague (50°N, 15°E) and Bamako (13°N, 8°W). The map depicts the world in a Lambert conic display at a scale of 1:115,000,000. The latitude of the undistorted parallel is 30° N. Give the result in millimeters and round to whole numbers.
10. What is the length of the 60 NW parallel in Sanson's 1:120,000,000 scale view? Round the result to whole millimeters.
Thank you for your help and reply
1. In what way are you going to receive help here if others solve your obvious homework problems?
2. We don't solve millions of questions per student.
3. Where are you stuck with question 1?
4. What effort have you made to solve question 1?
5. Post one question at a time.
#31 Re: Help Me ! » Solve for m » 2023-11-21 05:30:12
When I was first being taught how to solve quadratics, after factorisations, the teacher went on to show us 'completing the square'. It was a logical sequence of steps for me so I used it a lot. Then we were given the quadratic formula to memorise and told we could use that as well. My fellow students did that but they had to look up the formula every time or try to memorise it. I didn't want to do that, so I stuck with completing the square. It takes more lines but it's the same calculation. Then I tried it with ax^2 + bx + c = 0 and realised I was proving the formula.
So I switched to using the formula (which I still hadn't learnt) but I didn't look it up either. I re-proved it each time. Gradually I got better and better at this until I could imagine the steps in my head and write the formula from that.
So I'd managed to learn it by re-proving it every time. 58 years later and I can still do that. I was delighted when, in an exam, we were asked to prove the formula. Easy for me; tough for my 'memorising' friends.
So how does this address your post? Working from first principles reinforces understanding and makes it easier to remember. Things I have just memorised go straight out of my head again. If I develop a full understanding I can always do things but I sometimes I have to re-prove the formulas.
Bob
Bob,
1. Learning math formulas without knowing how to derive them is not learning mathematics correctly.
2. I never have trouble when using formulas. I just don't know how to derive them at any level. This keeps me at the amateur level of mathematics.
3. Not to step away from the topic at hand but I want to ask you 2 questions. WHAT DOES INDOCTRINATION OF STUDENTS MEAN? Does INDOCTRINATION have a lot to do with students not learning mathematics correctly?
#32 Re: Help Me ! » Radicand Comes Out » 2023-11-21 05:21:05
Let's not have an argument about what a poster says in helping. You have to let each person provide their help in their own way. If it doesn't help then you can ask for clarification or ignore it but please don't get angry. That doesn't help anyone. Remember my post about when I was trolled.
Bob
I am not angry. Frustrated is a better word. I want to improve mathematically. This is not possible if members provides the entire solution. If I ask for a step by step solution, that's a different story.
#33 Re: Help Me ! » Solve for F » 2023-11-21 05:11:14
the poster wrote:Is this OK so far?
I interpret this as meaning "Don't give me the whole answer but rather just tell me if I'm on track for an answer".
If someone wants to include the whole solution why not put it in hide tags so the OP doesn't see it but can refer to it to confirm their answer.
Bob
Exactly. Telling me the whole answer does not help at all.
#34 Re: Help Me ! » Probability of Red Section » 2023-11-21 05:08:42
That's right and demonstrates why I say solving depends on whether the regions are equal. Maybe the questioner intended you would assume that. But it is also possible that the intended point of the question is for you to realise that insufficient information has been given.
Bob
Insufficient data has been given. How do you know this?
#35 Re: Help Me ! » Venn Diagram Mathematics » 2023-11-21 05:07:04
Draw three overlapping circles. There are 8 regions including the outside (= 18)
Label each circle like this H = 20 etc but do not put this number inside any of the regions. The number in a region should be the number who do just those sports. There's no easy way to fill in the individual numbers because, although enough information given, you cannot immediately calculate any region yet.
So put x for the number in H + C + F, the middle region. (Cannot find a symbol for intersection in the list above the posts)
Then write expressions for H + C + F' = 7 in terms of x and the other two sport regions.
Continue writing in expressions with x in them for all the regions and hence form an equation for x.
Bob
I drew 3 circles as you suggested but was unable to form the needed equation.
#36 Re: Help Me ! » Find Student Score » 2023-11-21 05:04:00
Use 78 and 4 to find the total (T) for four tests.
Make an expression including x (the fifth score), T and the total for five tests.
Bob
Sorry but I don't understand what you mean.
#37 Re: Help Me ! » Sum of All Even Integers » 2023-11-21 05:02:53
sum of all the even integers between 99 and 301?
The formula works for sets of integers that do not have any gaps so use the fact that evens are involved to get a continuous sequence of integers. ie:
100 + 102 + ... + 300 = 2 x (50 + 51 + ... 150)
So find ∑49 and ∑150, subtract and then x2.
Bob
What do you mean by x2? Did you mean to type x^2?
Why must I subtract x2 or x^2 from the sum of
∑49 and ∑150?
#38 Help Me ! » Product Promotion Application » 2023-11-21 04:58:46
- sologuitar
- Replies: 6
A cereal company finds that the number of people who will buy one of its products in the first month that the product is introduced is linearly related to the amount of money it spends on advertising. If it spends $40,000 on advertising, then 100,000 boxes of cereal will be sold and if it spends $60,000, then 200,000 boxes will be sold. Write a linear equation that relates the amount A spent on advertising to the number of x boxes the company aims to sell.
The answer is y = (1/5)x + 20,000.
I would like a step by step reply that will display how the equation was formed based on the information in the application.
#39 Help Me ! » Access Ramp » 2023-11-21 04:48:11
- sologuitar
- Replies: 6
A wooden ramp is being built to reach a platform that sits 30 inches above the floor. The ramp drops 2 inches for every 25-inch run. Write a linear equation that relates the height y of the ramp above the floor to the horizontal distance x from the platform.
The answer is y = (-2/25)x + 30
Question:
Can I please have a step by step explanation of how this linear equation is form?
#40 Help Me ! » Find A Linear Equation » 2023-11-21 04:41:42
- sologuitar
- Replies: 9
The relationship between Celsius (°C) and Fahrenheit (°F) degrees of measuring temperature is linear. Find a linear equation relating °C and °F if 0°C corresponds to 32°F and 100°C corresponds to 212°F.
Can I get a few hints?
#41 Help Me ! » Complex Numbers » 2023-11-21 03:52:35
- sologuitar
- Replies: 4
Write the expression in the standard form a + bi.
6i^3 + 4i^5
6(-i) + 4(i)
-6i + 4i
My answer = -2i
Textbook answer = -10i
Why is my answer wrong?
#42 Help Me ! » Standard Form a + bi » 2023-11-21 03:46:28
- sologuitar
- Replies: 4
Write each expression in the standard form a + bi.
A. i^(23)
I say i^(23) can be expressed as (i^5)(i^4)(i^3).
i^5 = i
i^4 = 1
i^3 = -i
(i)(1)(-i) = (i)(-i) = -(i^2) = i(-1) = -I
You say?
B. i^(-15)
I think the first step is to remove the negative power.
So, i^(-15) = 1/(i^15)
i^(15) = (i^5)^3
i^5 = i
I now have 1/(i)^3 = 1/(i^3) = 1/-i
My answer = 1/-I.
Textbook answer = I
What did I do wrong with B?
#43 Help Me ! » Sum of All Even Integers » 2023-11-20 18:37:35
- sologuitar
- Replies: 11
For any positive integer n, the sum of the first n positive integers equals n(n+1)/2. What is the sum of all the even integers between 99 and 301?
A. 10,100
B. 20,200
C. 22,650
D. 40,200
E. 45,150
Can someone set this up for me?
#44 Help Me ! » Find Student Score » 2023-11-20 18:32:50
- sologuitar
- Replies: 7
A student's average (arithmetic mean) test score on 4 tests is 78. What must be the student's score on a 5th test for the student's average score on the 5 tests to be 80?
(A) 80
(B) 82
(C) 84
(D) 86
(E) 88
Can someone set this up for me?
#45 Help Me ! » Venn Diagram Mathematics » 2023-11-20 18:28:18
- sologuitar
- Replies: 8
In a class of 50 students, 20 play Hockey, 15 play Cricket and 11 play Football. 7 play both Hockey and Cricket, 4 play Cricket and Football and 5 play Hockey and football. If 18 students do not play any of these given sports, how many students play exactly two of these sports?
A. 12
B. 10
C. 11
D. 15
E. 14
Can someone set this up for me?
#46 Re: Help Me ! » Probability of Red Section » 2023-11-20 18:16:46
Bob wrote:Correct if we assume the sections are equal in area. If this is not the case then it is not possible to determine the probability.
sologuitar wrote:Can you explain what you mean?
what would happen if one of the sections is, say, half of the wheel
In that case, the probability is 1/2.
#47 Re: Help Me ! » Company's Profit or Loss » 2023-11-20 15:27:49
Now, to find the profit or loss, subtract the total cost from the total revenue: $18,000 (Total revenue) - $15,750 (Total cost) = $2,250 So, the company's profit on the sale of 2,250 units is $2,250.
Cool. Moving on....
#48 Re: Help Me ! » Probability of Red Section » 2023-11-20 15:26:49
Correct if we assume the sections are equal in area. If this is not the case then it is not possible to determine the probability.
B
Can you explain what you mean?
#49 Re: Help Me ! » Solve for F » 2023-11-20 12:38:14
In the right direction.
Please, don't solve the problem unless I ask you to do so. Otherwise, my self-study time is a waste of energy.
#50 Re: Help Me ! » Solve for F » 2023-11-20 12:37:08
sologuitar wrote:Solve C = (5/9)(F - 32) for F.
You continue solving my problems without me asking you to do so. How am I ever going to learn this stuff, brother?