# INMO 2017

Note by The almighty Knows It All.
2 years, 9 months ago

This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.

When posting on Brilliant:

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Problem 5:
Part 1
Part 2

- 2 years, 9 months ago

Nice Bro!! Both ur Solution and Bedsheet!

- 2 years, 9 months ago

hahaha.lol.Thanks

- 2 years, 9 months ago

SOLUTION TO 1

- 2 years, 9 months ago

@Rohit Camfar, same as mine.

But i calculated inradius for DEH where H is intersection of D'E with AD, instead of D'EG as both are congruent or exactly copy of each other.

That was much simpler.

- 2 years, 9 months ago

I think there would not have been much difference in solution then.

- 2 years, 9 months ago

Yes i said same as yours. I took side of square as 1 just for simplicity as side does not alter the proof.

- 2 years, 9 months ago

nice solution. much differernt than mine. I think INMO problem setters like incenters.@Priyanshu Mishra why dont u join in the discussion in our team. U dont participate at all.

- 2 years, 9 months ago

Where to join and chat?

- 2 years, 9 months ago

in slack.I had invited u. u had joined it some months ago.

- 2 years, 9 months ago

How did you obtain the value of 'a'?

- 2 years, 7 months ago

I guess you can see the last stanza of the first page of my solution. Your profile tells that your age is 14. So, I think that you are an IMO aspirant. Would you like to join us on Slack?

- 2 years, 7 months ago

I saw the last stanza of the first page of your solution, but I'm not getting the value of 'a' as you got after simplifying... Can you please elaborate that simplification?

And yeah, I would like to join you all :)

- 2 years, 7 months ago

That's nice if you want to join. You can join us on slack by the end of this month as the owners are into their board exams and I am also out preparing for the exams.

- 2 years, 7 months ago

Yeah, I'll join by the end of the month. By the way, thanks for elaborating the simplification... :)

- 2 years, 7 months ago

u can give ur email id if u want to join.

- 2 years, 7 months ago

My email id is ojaseeduble@gmail.com

- 2 years, 7 months ago

Rohit could you add me on Slack. I am too an IMO aspirant.

- 2 years, 6 months ago

Ok, give @Ayush Rai your email. And you can first join the Brilliant's official team-- Click here

- 2 years, 6 months ago

@Ayush Rai @Rohit Camfar - alternative method using lengths rather than angles- it uses the fact that the height from the right angle to the hypotenuse is always $\frac{ab}{c}$, and the radius of an incircle is always $\frac{ab}{a+b+c}$, where $a$, $b$ and $c$ are the lengths of a right-angled triangle and $c$ is the hypotenuse. Do this multiple times to prove that PQX forms an isosceles right angled triangle. You can also say that tangents that meet are the same length. Sorry I didn't write up all of the working, I'm in the middle of lunch:) Not going to lie, the geometry problems in this Indian MO are miles harder than those in the BMO, you guys are doing really well!

- 2 years, 9 months ago

Well India is the best! And all are rest (I hope you too agree @Sharky Kesa). Well Nice solution. It is from INMO your BMO should be compared with RMO. Well try the others too @Dan Ley.

- 2 years, 9 months ago

An another thing : You wrote "Sorry I didn't write up all of the working, I'm in the middle of lunch:)" Really, are you in the middle of shool lunch?

- 2 years, 9 months ago

Of course haha I wish I lived in Asia. Is RMO easier or harder? I'll have a look at the 1st one some time, it looks fun, but no promises:) Yes it's 13:15 here! Showed my friends these questions, they're good!

- 2 years, 9 months ago

That is easier.

- 2 years, 9 months ago

nice one @Dan Ley

- 2 years, 9 months ago

this diagram looks like ur passel of techniques problem @Rohit Camfar

- 2 years, 9 months ago

hahahah Yup I remember I too thought the same. Two circles. That too was a nice one. See this if you don't know what is Passel of TechniquesFor those who haven't seen passel of techniques

- 2 years, 9 months ago

Passel of techniques was fun;) Thanks @Ayush Rai Question: are you two at the same school?

- 2 years, 9 months ago

Nope. He is in Bangalore and I am in JK. => IF he is in Liverpool then I am in Glasgow.

- 2 years, 9 months ago

Haha, both Liverpool and Glasgow are very far from where I live! But I understand what you mean;) So is the RMO the first round then? We have the SMC (Senior Maths Challenge) before the BMO1 (British Mathematical Olympiad)- the top 1000 do BMO1 and the top 100 then do BMO 2;)

- 2 years, 9 months ago

yes RMO is the first round.U are studying which class?

- 2 years, 9 months ago

I study A-levels in Maths, Furthermaths, Physics and Chemistry:) Applied to University to do Engineering;) Are you still doing many different subjects?

- 2 years, 9 months ago

Yes I have to do it for another three years.

- 2 years, 9 months ago

Ayush has do do it for another two years. He is 1 year senior to me.

- 2 years, 9 months ago

Wow, you're well ahead of the game for maths though- thoughts for university, do you both want to study maths?

- 2 years, 9 months ago

yes I want to study maths.

- 2 years, 9 months ago

dan ley, I invite u to my RMO,INMO group in slack. If u are interested u can give ur email id.

- 2 years, 9 months ago

@achal jain u can also join by giving ur email address

- 2 years, 9 months ago

Yes we will discuss problems there. That would be fun.....

- 2 years, 9 months ago

@Dan Ley Are you interested?

- 2 years, 9 months ago

Well right now I am just aiming for RMO.

- 2 years, 9 months ago

No we aren't in the same school. Well we have a team for RMO,INMO prep. where we discuss problems in slack.

- 2 years, 9 months ago

Problem 1:

- 2 years, 9 months ago

Everyone lets rock. Post your solutions. Well I would like to notify some people to begin @Sharky Kesa , @Neel Khare , @Ayush Rai , @ Hrithik Nambiar , @Dan Ley , @abhishek alva Guys I don't remember anybody else's name.

- 2 years, 9 months ago

and also @Priyanshu Mishra , @Md Zuhair

- 2 years, 9 months ago

@Ayush Rai, How many you solved at INMO?

I did 1, 2,4,6 only. I am uncertain about my selection.

- 2 years, 9 months ago

I didn't write Inmo.solved 1,4,5

- 2 years, 9 months ago

How you got 5?

- 2 years, 9 months ago

You can see above?

- 2 years, 9 months ago

How much did you get in INMO?

- 2 years, 8 months ago

Problem 5 part 2. Well first part of AYUSH is the best possible. Here is a short for 2nd one.

- 2 years, 9 months ago

Problem NO 4

- 2 years, 9 months ago

We hve got our scorecards,lets share our marks

- 2 years, 8 months ago

Tell yours Ayush.. and which region are you from?

- 2 years, 8 months ago

i didnt write INMO

- 2 years, 8 months ago

1. I think the cut off must be more than 70.

- 2 years, 7 months ago

How much did you score Priyanshu??

- 2 years, 7 months ago

54 only.

- 2 years, 7 months ago

I got 49- maybe I lost few marks in the 4th question where the silliest mistake of my life helped to get 4 solutions instead of 3 - of course i wouldn't have qualified even if i had got it corect.(and I had a different solution than the official ones)

- 2 years, 6 months ago

oh thats a good score.:)

- 2 years, 6 months ago

Tnx , but end of the day ,nothing to gain,right??

- 2 years, 5 months ago

U just gained some knowledge through ur preparations! Don't feel bad!

- 2 years, 5 months ago

from Odisha

- 2 years, 6 months ago