₦airaland Forum

Goalnaldo:
so the answer is not complete yet?

Look up now. The solution is there. Let me tag you on it so you can get it.

dejt4u:
but in reality, this is not valid

How is it not valid bro in reality?? If you have a group of 100 people, the probability that none will share same birthday is almost non existent. The probability that at least 2 people will share the same birthday will be quite high. Therefore, it is very valid in reality.

jackpot:
Maybe we should try to simulate it using real data. This is the [url]https://img.fifa.com/image/upload/hzfqyndmnqazczvc5xdb.pdf [/url]for 2018 fifa world cup data with the players birthdays.

We can decide to pick any consecutive 100 players. Either from top, middle or bottom.

Let's go!

Did you see the solution I posted?

dejt4u:
I think I like this

Question is quite tricky and requires a high thought process. Will get a calculator to compute final answer soon.

jackpot:
Among a group of 100 random students, what is the expected number of students who don't share birthdays with others in the group?

Note: by birthday, it means same month and day, and not necessarily year.


Assumptions: none of the students were born on February 29 and that number of days in a year is 365.

Mrshape, dejt4u, martinez39s, Richiez, mathefaro, naturalwaves, other mathematicians please help

SOLUTION
We need to take a step by step approach in order to get this.
Since 29th of February is not included, this means that we are dealing with just 365 days.
Having said that, what is the expected probability of the 1st student? That is going to be 365/365 days
What is the expected probability of the 2nd student? 364/365
Third? 363/365
Fourth....362/365
Fifth..................361/365
This is how it will go on till we get to the 100th student which will be 266/365 but we cannot do this as it will be too cumbersome.
Now, let us sort the denominator. Every component in the denominator is 365 i.e 365/365 * 364/365 * 363/365................*266/365.
This means that the denominator will be 365¹⁰⁰.

How about the numerator? We have 365! but we are not going to be needing the whole of it. We only need the area from 365 to 266. How do we get this?
All we need do is to divide 365! by 265!.

Thus, the desired solution to the problem is;
(365!) / (265! * 365¹⁰⁰).

Modified:
So, I have gotten a calculator,
(365!) / (265! * 365¹⁰⁰). = 3.0725 * 10^-7 approximately.
That is around 0.00000030725 approx.
As you can see, the probability is very slim as it is almost unlikely that out of 100 students, none will share a birthday which makes a lot of sense.

cc: Jackpot, Dejt4u, Martinez39s, Mrshape, Richiez, mathefaro,ifada123, Goalnaldo

This is also one of the best advanced calculators available: https://keisan.casio.com/calculator

Good morning,
My phone's earpiece is bad. I can only hear when it is on speaker or when I use an external earpiece. How do I fix this and how long will it take? Redmi note 7 pro

Mrshape:
How much will you pay?

You have now turned to something else o with this your new found money dimension. I've been solving questions for people here for years without collecting a dime and same applies to a whole lot of other contributors.

zeenaman:
One thing I notice about Maths gurus is that they speak horrible English. Is it not possible to be good at both Maths and English?

I'm an exception to your observation. Lol

Olumighty123:
I am not a surgeon but I have a friend who is, he was operating on a patient to remove his kidney then he found a laser fiber, a bad surgeon had left it inside during the patient previous surgery.

See where you took your lies from. Say No to plagiarism.
Or is Walid your said friend?

Ekakamba:
Mods! Do the needful.

He is a bloody liar. That didn't heppen to his friend.
He even removed all the details as narrated from Quora.

Olumighty123:
I am not a surgeon but I have a friend who is, he was operating on a patient to remove his kidney then he found a laser fiber, a bad surgeon had left it inside during the patient previous surgery.

Keep on concocting lies from the pit of hell.
You are not serious at all. You stole a post from Quora and tagged it as your friend. Can you not reference a source when you take something from there??

englishmart:
You're comparing two people using a superlative adjective. Laughing in Boko Haram dialet

dialect.

This is not 2012 model. Check well.

AshiraWealthy:
Thanks for the insults. Ive modified it. But Im sure you saw where i stated that I should be excused for any misinterpretation or wrong terminology at the beginning of this write up?
I'll take this in good fate as its not my field and I already clearly stated that.

What is your field?

EBUBS:
Make your calculation with crude and not crudity

Crudity and Attitude are both nouns. So, I do not understand your point
Moreover, is that all you could bring out from all that was said?

Mrshape:
I am not the creator but I found this to be Very interesting & such a meaningful message 2 share:

*If:*
*A = 1 ; B = 2 ; C = 3 ; D = 4 ;*
*E = 5 ; F = 6 ; G = 7 ; H = 8 ;*
*I = 9 ; J = 10 ; K = 11 ; L = 12 ;*
*M = 13 ; N = 14 ; O = 15 ; P = 16 ;*
*Q = 17 ; R = 18 ; S = 19 ; T = 20 ;*
*U = 21 ; V = 22 ; W = 23 ; X =24 ;*
*Y = 25 ; Z = 26.*

*Then,*

*H+A+R+D+W+O+R+K*
=8+1+18+4+23+15+18+11
*= 98%*

*K+N+O+W+L+E+D+G+E*
=11+14+15+23+12+5+4+7+5
*=96%*

*L+O+V+E*
= 12+15+22+5
*= 54%*

*L+U+C+K ;*
=12+21+3+11
*= 47%*

*None of them makes 100%.*
*Then what makes 100%?*

*Is it Money?*
.
.
.
*NO!*

*M+O+N+E+Y*
= 13+15+14+5+25
*=72%*

*Leadership?*
.
.
.
*NO!*

*L+E+A+D+E+R+S+H+I+P*
=12+5+1+4+5+18+19+8+9+16
*=97%*

*Every problem has a solution, only if we perhaps change our*

*"ATTITUDE"...*

*A+T+T+I+T+U+D+E ;*
1+20+20+9+20+21+4+5
*= 100%*

*It is therefore OUR ATTITUDE towards Life* *and Work that makes*
*OUR Life 100% Successful.*

*Amazing mathematics

� *who ever created this is a genius *great msg*�����✨✨✨���✨✨��

I cannot believe that you would be the one to share something like this that defies logic.
Anyway,
If you write a computer program for this,
You will get 2,302 words that will add up to exactly 100

Amongst those words, a whole lot will not be positive

E. G

The word CRUDITY

C+R+U+D+I+T+Y

3+18+21+4+9+20+25 = 100%

Should we start being crude because CRUDITY adds up to 100%?

annie17:
how can i contact u sir,i really need a mentor in maths please,you will be doing my life a great favour.

Zero.....

The defence is not only stewpid but foolish
So, if you procure wheelbarrows for works, you will commission the wheelbarrow?
Establishments that usually procure heavy equipment do not even put a tape round it for commissioning talk more of wheelbarrows. This is the worst damage control in history. The idiota that was hired to do this damage control should be fired.

Enskynelson:
You can apply for admission and start your program every semester

That is great!
Thank you.

Anthonyo15:
Coming soon!!!

Can you apply for Masters like after 1st semester? In the middle of the year? Or it has to be every 1st semester?

Sammy07:
I Swear

It is such a big shame!

Sammy07:
Is like you guys went to a polytechnic or college of education.

You do not read the article, you only read the headline and comment.

The governor said and I quote.

"Akeredolu while speaking on the absence of Babajide Sanwo-Olu, governor of Lagos, at the event which held in Ibadan, Oyo state, said Sanwo-Olu had planned to fly into Oyo but could not do so because of the weather.

He said, “I must convey the apologies of two of our governors who are not here. What has happened is part of problems you face in harmattan period, particularly when you are not from a rich state."

Osaze007, Legendhero, Afamed.
I give up on SE guys...

Those guys you quoted are all ediots. School did not pass through them. The statement itself was a joke.

Jodha:
But a quadratic equation can be solved with fraction while using the almighty formula right?

Yes now.
Check your solution.
Your base is even wrong. Your denominator is supposed to be 2 x - 5/2 and not 2 x 10.

Jodha:
Can yhu pls calculate it again without multiplying both sides by 2 .... It's possible to solve it with the fraction right?

Yet the answer yhu got using the almighty formula... seems quite different from the one yhu got us the new method...

I don't think the method is reliable

It is not different. It is the same thing dear. Simplify the answers gotten from the quadratic. It is same as what I got.

2(1+2 root 6i)/5, or 2(1-2root6i)/5
0.4(1+2root 6i), 0.4(1-2root6i)
0.4 +1.96i or 0.4-1.96i

Did you see that it is the same thing now?

The method is very very reliable.
If you know who Po-Shen Lo is, you wouldn't even say the method isn't reliable.

Jodha:
It's been long i calculated...but i thought...

Oh well... that's the only issue right?

I have edited my comment to come with solution. Look up, you will see it. Better still, let me repaste the quadratic solution again.

Jodha:
I watched the video...thanks alot...

So i solved it again...look...

The solution is not correct dear.
How do you find the square root of a negative number?
There must be a complex number in your solution but there is none. You should get the exact thing I have below when you use quadratic formula.
Note that the answer given here is same as what I got when I used Loh's methods.

Jodha:
-5/2X²+2X-3=7

Can yhu pls throw more light on the "De Moivre's" theorem?

Okay, Let me try this,
Multiply through by 2 and modify equation to obtain,
5x² -4x +20=0
Observe that the coefficient of x² is not 1
So,
divide through by 5 to get,
X²- (4/5)X + 4= 0
Using Loh's theorem,
Half way through 4/5 is 0.4
Hence,
( 0.4+u)(0.4-u)=4
0.16- u²=4
u²= -3.84
u= square root of (-3.84)
u= square root of [(3.84)(-1)]
u= 1.96i (Note: In complex number, square root of -1= i)
Our answers are (0.4+1.96i) and (0.4-1.96i)
As for De Moivre's theorem, let me give you one of the videos from Eddie Woo. He takes his time to explain concepts.
Check through some of his other videos. He is a good teacher.

https://www.youtube.com/watch?v=Qha-Lsdj5xo

Jodha:
Oh i see... thanks a lot ...

For once I've learnt something new here ..

Jodha:
If it isn't like the question...the op asked...what do we do?

Give any example of a quadratic equation that is not in that form. Let me solve it using that method. Preferably, give one whose coefficient of X² is not 1.

enawt:
I totally get you mahn. I just know it becomes complex when you tackling harder quadratic equations. There are many equations you can't solve using factorization method

Yeah sure but this method works well for a wide range because of that middle interval method. The method is basically for secondary school students but still works fine for even decimal answers that an ordinary factorisation method would not solve.

BitCraftman:
For the 1st one, add all three numbers at the edges of the triangle and multiply by 2.

For the second, multiply the numbers on top by number on bottom to get number on the left right. Add top + bottom then square it to get number on right left box.

Dont mind me. I know it was a typo.
I've helped you with the correction.
You're welcome!