Math / Science

The Math / Science topic primarily includes discussions of mathematics, physics, statistics and economic analysis, but also biology, chemistry and other sciences.

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How to calculate ''32% Undergraduate Grade Point Average?
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I am trying to find the term used in chemistry to describe the tendency of a 2-way chemical reaction to prefer one chemical combination over the other, such as in Keto-Enol in organic chemistry. I can only recall using the term affinity, but that is not precisely what I am looking for.

This is a follow-up question to a previous thread located here:

Auto-fill a cell's color based on numeric RGB values and vice versa in Excel

In that thread, the solution (by Ejgil Hedegaard) includes an attached Excel file in which the fill color of a particular cell, automatically changes in response to entering various values in three other cells labeled R (red), G (green), & B (blue).

This functionality is tremendously useful for me (and I suspect will be for others) because it enables you to instantly view the new color resulting from changes in any of the RGB parameters (ie without the necessity of the four clicks typically required to obtain that information):

        Home > Fill Color > More Colors > Custom

(The file also includes a chart for quickly converting from RGB decimal to RGB hex and vice versa.)

Additionally, the solution to the thread contains the formula for calculating Excel's color code:

        ExcelColor = R + G *256 + B *256^2

For example:

        Red = 204
        Green = 102
        Blue = 255

is calculated as follows:

        ExcelColor = 204 + (102*256) + (255*256^2)
        ExcelColor = 16737996

It also displays the following for reversing the process (ie :

        R = C Mod 256
        G = C \ 256 Mod 256
        B = C \ 256^2 Mod 256

Are these three formulas math or code and what is the purpose of the backslash?

I'd like to take a list of intervals defined by pairs of numbers, eg

and convert this into a consolidated list counting any overlapping intervals as one, so the above example would give:

See attached drawing that illustrates this.

I want to do this with array/matrix operations, if possible, so I can implement in google sheets without coding.

Can you guys please suggest me some good free web sites for the preparation of mcat exam?

I remember from my days of teaching school science that we used to demagnetize nails by hitting them with a hammer and magnetize them by stroking with a magnet until the atoms aligned in the same direction.

My friend was showing me an app on his phone where the accelerometer sometimes fails and you are advised to reset it by moving the phone in a figure of 8. I was curious why the figure of 8. I'll break my question into 2 separate parts as that's what my feeble brain needs :)  If you are kind enough to respond to this, please can you address the sub-questions in turn. For simplicity I am assuming the accelerometer is just a magnet

a) When atoms reorient themselves to be magnetized do they turn clockwise, anticlockwise or both directions (just curious)?
b) How does the figure of 8 movement reset a magnet? The electromagnetic field lines on either side of a bar magnet do look like a figure of 8 on its side. My days of knowing electromagnetism are long gone but is it a fair simplification to say by following the magnetic field lines that should be around your phone if its magnet were 'working,' you actually realign the atoms in the magnet. If that is the case I'm not sure how this works as it is not as obvious as the notion of  stroking a nail with a magnet to realign the atoms. If my simplification is correct I do not need to know how this works as that probably requires a physics degree so all I would ask is that confirm or disconfirm my suggestion (unless …
It's my math problem I'm struck
A workshop table has an equilateral triangular top each side 900mm the legs are on the three corners . A load of 500N is placed on the table at point distant 325mm from one leg and 625mm from another . What is the load on each of the three legs
NEED  HELP Blocks with masses of 2.0 kg, 3.0 kg, and 4.0 kg are lined up in a row on a frictionless table. All three are pushed forward by a 11 N force applied to the 2.0 kg block.
I have an irregular figure with the sides of 7,7,5,10. What is the area and perimeter of this shape?
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I'm blanking out here on proper terminology. Suppose I have an array (e.g. of seasonal records for a sports team).

2016: Wins: 8. Losses; 2.  Percentage: 80.00
2017: Wins: 4: Losses: 6.  Percentage: 40.00

The dataset also contains a totals object:
Wins:  12: Losses: 8. Percentage: 60.00

Wins &  Losses are the SUM of the individual elements. But, what's the term for the Percentage (60.00). Aggregate?

Need the above for an API guide.
One of the datacenters a company uses is a converted nuclear shelter.
Switzerland, paranoid about security, has enough nuclear shelters to protect all of its inhabitants. Imagine if we converted all of these nuclear shelters to power racks and racks of standard 1U servers instead. How many servers can we support? Make your best guess and round your answer to the nearest million.
A company's email product runs in the browser and supports multiple composers windows (the box where you write an email). Imagine a browser window of width L. Each composer has width W. There are a total of N composers. When the number N is large, composer windows must overlap so that all composers can fit within width L. Each composer has the same overlap X. What is X in terms of N, W, and L?
Parliament has 100 seats. Only parties with strictly more than 5% of votes can qualify to get seats. There are 12 parties participating. Seats are distributed to the parties that qualify to get seats, proportionally to their votes. Votes are strictly for 1 party (no voting for multiple parties or no party).
What is the maximum number of seats that a party with 25% of the votes can get?

Say you're shopping for some ingredients which come in standard pack sizes of either 100g, 250g or 500g, having prices $0.40, $0.75 and $1.00 respectively.

Depending on the exact quantity you need, you can choose to optimise your choice of pack purchases according to price or minimum wastage, or perhaps some combination of the two.

For example if you need 350g, you could buy 1 x 500g pack for $1.00, and waste 150g, or buy 1 x 250g + 1x100g at a cost of $1.15 and have no wastage.

Given the quantity you need, how could you optimise your pack selection mathematically? (a) for minimum cost, and (b) for minimum wastage?

ie some function(quantity needed) gives the pack sizes and quantities to buy, eg:
f_mincost(350) outputs 1 x 500g
f_minwaste(350) outputs 1 x 250g, 1 x 100g

Here is a spreadsheet with some more examples:

Many thanks
A fair coin is tossed 200 times. Find the probability of getting a head an odd number of times
Sol: the number of cases favourable to E is 200C1 + 200C3 +200C5 +200C7 +200C9…. +200C199  = (2200/2)

Dear experts,

Can someone throw more light on the above binomial equation for counting odd number of items which results 2n-1.
Similar will the result change if were to add the even number of times.
What about for adding for all cases where r=prime number and less than ≤n

Kindly help.
I have here what I think is a classical O.R. (operations research) problem. I'm looking to formulate it mathematically and look at the options available to solve it.

We have a list of say 100 recipes.

These recipes combined use 400 ingredients.

The quantity of ingredients required for all the recipes could be defined by a matrix dimension 100 x 400.

We can combine recipes into meal plans, so that the ingredients required for a meal plan is the total of the ingredients required for each recipe in the meal plan.

Each ingredient has an associated cost, that varies depending on the quantity bought.

Say the cost variations can be expressed with no more than 5 cost buckets per ingredient. Eg.

Bucket, Cost / kg
< 1kg, £4.00
1-5kg, £3.50
5-20kg, £3.00
20-100kg, £2.80
> 100kg, £2.50

The ingredient costs can be expressed in two matrices each of dimension 400 x 5:
a) One matrix 400 x 5 giving the buckets for each ingredient
b) Another matrix 400 x 5 giving the unit costs per ingredient and bucket number (1 to 5)

A given meal plan will have a given ingredient requirement, with associated total cost determined via the above matrices.

Suppose we constrain the number of meals in the meal plan to say 4 meals, and these 4 meals must be different recipes. For simplicity (!) we have no other constraints for now.

Our objective is to choose our meal plan (4 meals) such that the total cost is minimised.

1. How do we formulate this problem?
There are huge amount of different slot machines available online, like in the given list here All of them powered by own random generated algorithm. So I would like to know if there some strategies to play slots? I mean when you are playing for money and you want to make even a little profit and it would be great it the strategy does not include loosing money. Researches and publications are appreciated too.
The market research department at a manufacturing plant determines that 20% of the
people who purchase the plant’s product during any month will not purchase it in the
next month. On the other hand, 30% of the people who do not purchase the product
during any month will purchase it the next month. In a population of 1000 people, 100
people purchased the product this month. How many will purchase the product in 2 months?
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Hi Experts,

I have tried to round off a value x = 455.77 using math .round() function but not rounded the value 466.

Code I have given to round off:

var rounded = Math.Round(x, 2, MidpointRounding.AwayFromZero);

Open in new window

Could you guys please explain whats wrong here?

Anjala Baby
Dear Experts,

Actually learning the basic of Machine Learning through the following link:

That contains an url url = "" which have the data of 150 records from the iris dataset, but I would like to test the results on more records.

Could you please advise is there on the internet availabe more iris data for free to download?

Thanks in advance,
317.2 feets , 297feets , 338feets , 325feets .... Find the total area in acres
Hey, All,

Can you give me some good web links to where it has some very good Data Scientist Resume samples? Also, those samples are one-pagers (everyone desire one page resumes)

The user is asked to input the distance, yards they want to converted to miles. The distance must be input and stored (as a variable) as an integer, not as a double. The output is the distance in miles (also as an integer) together with an explanatory message. There are 1760 yards in one miles
Watching this 6 minute video, I leaned HAARP shoots 72,000 times the maximum amount of energy for an AM station in the United States.

My question is what's a better analogy?

For example, how much energy is that compared to the output of a small nuclear plant?

I am just having a hard time sensing the scope of the comparison they created and hope someone can come up with a better description.


Math / Science

The Math / Science topic primarily includes discussions of mathematics, physics, statistics and economic analysis, but also biology, chemistry and other sciences.