The city has just opened its

one-of-a-kind Fabergé Egg Museum with a single egg displayed on each floor

of a 100-story building. And the world’s most notorious jewel thief

already has her eyes on the prize. Because security is tight

and the eggs are so large, she’ll only get the chance to steal one by dropping it out the window

into her waiting truck and repelling down

before the police can arrive. All eggs are identical in weight

and construction, but each floor’s egg is more rare

and valuable than the one below it. While the thief would naturally like

to take the priceless egg at the top, she suspects it won’t survive

a 100-story drop. Being pragmatic, she decides to settle

for the most expensive egg she can get. In the museum’s gift shop,

she finds two souvenir eggs, perfect replicas

that are perfectly worthless. The plan is to test drop them to find the highest floor

at which an egg will survive the fall without breaking. Of course, the experiment

can only be repeated until both replica eggs are smashed. And throwing souvenirs out the window

too many times is probably going to draw

the guards’ attention. What’s the least number of tries

it would take to guarantee that

she find the right floor? Pause here if you want

to figure it out for yourself! Answer in: 3 Answer in: 2 Answer in: 1 If you’re having trouble getting started

on the solution, it might help to start

with a simpler scenario. Imagine our thief only

had one replica egg. She’d have a single option: To start by dropping it

from the first floor and go up one by one until it breaks. Then she’d know that the floor below that is the one she needs

to target for the real heist. But this could require

as many as 100 tries. Having an additional replica egg

gives the thief a better option. She can drop the first egg from different

floors at larger intervals in order to narrow down the range

where the critical floor can be found. And once the first breaks, she can use the second egg to explore

that interval floor by floor. Large floor intervals don’t work great. In the worst case scenario, they require

many tests with the second egg. Smaller intervals work much better. For example, if she starts by dropping

the first egg from every 10th floor, once it breaks, she’ll only have to test

the nine floors below. That means it’ll take at most

19 tries to find the right floor. But can she do even better? After all, there’s no reason

every interval has to be the same size. Let’s say there were only ten floors. The thief could test this whole building

with just four total throws by dropping the first egg

at floors four, seven, and nine. If it broke at floor four, it would take

up to three throws of the second egg to find the exact floor. If it broke at seven, it would take up to two throws

with the second egg. And if it broke at floor nine, it would take just one more

throw of the second egg. Intuitively, what we’re trying to do here

is divide the building into sections where no matter which floor is correct, it takes up to the same number

of throws to find it. We want each interval to be one floor

smaller than the last. This equation can help us solve

for the first floor we need to start with in the 100 floor building. There are several ways

to solve this equation, including trial and error. If we plug in two for n,

that equation would look like this. If we plug in three, we get this. So we can find the first n to pass 100 by adding more terms

until we get to our answer, which is 14. And so our thief starts on the 14th floor, moving up to the 27th, the 39th, and so on, for a maximum of 14 drops. Like the old saying goes, you can’t

pull a heist without breaking a few eggs.

Thank you so much to everyone who has supported our nonprofit mission on Patreon! You make this work possible. Want to learn more about how you can get involved? Check out our Patreon page: http://bit.ly/2zn58I6

Just grab the egg from floor 100 and use a glider to get out…

2 mistakes. One, if all are exactly the same, one can't be rarer and more valuable than another. Two, it should be "What's the least number of times it would take to guarantee that she finds the right floor," not FIND the right floor

Didn’t anyone think that if you keep dropping the same egg it will get in worse condition and break?

I'll

I liked it

TedEd: You can do it 19 tries!

Me: You could do it with 2 with 1 egg of you’re lucky

In real life that egg will break on the first floor

Like, can't you just keep a soft cushion or something to break the fall and/or soften the landing?

Beelzebub +297 Descended on PADX redirected me here.

http://www.puzzledragonx.com/en/mission.asp?m=3435

Comment section

If there are many trials possible, and she can go down to collect the replica egg timely, Can't we make it more easier to just replace the top floor egg with replica and run away?? Just one trial needed.

So how do you prove that with equal intervals of floors, 19 is the answer?

Make x chunks of the total number of floors. So each chunk has 100/x floors in it.

Suppose the egg breaks on floor 99 (because this will give us the maximum number of tries).

First, we throw the first egg after each 100/x number of floors. So we end up trying the first egg x times until it breaks on floor 100.

Next, we try the second egg 100/x – 1 times and it breaks on floor 99.

So the goal is minimize: x + 100/x – 1

take first derivative and equate to zero, we get x=10

take second derivative, and we get it to be positive at x=10.

therefore, at x=10, that equation has the minimum value.

So total number of tries = 10 + 100/10 – 1 = 19

Thank me if you want to. This is what I did before I heard him say that we don't need equal intervals of floors -_-

this was the only one I could solve

Classic dynamic programming problem.

Why are we helping thieves steal eggs?

Answer will be 7. Because it just like searching algo. With answer ceil(log 100).

In 7th search any required floor will be found please like if u agree so that it will be in top….i hope computer science student will understand.

Or put a cushion at the bottom.

Thief: throws 14 eggs

Guard: oh well I guess you tried

Also the police would have arrive already by throwing 14 eggs

No, i will not help in crime

Thief: Repels down the building after dropping the egg using a rope. Drops 14 sample eggs to get the most valuable one.

Also Thief: Can't carry a bag and simply repel down the rope with the egg on the 100th floor in her backpack easily and drive away.

Ted-Ed: Lets teach these kids how to rob things with math guys

these are raw eggs?

Why not just sell one of the souvenir eggs as one of the actual eggs if the souvenirs are exact replicas

I can solve it in less time trying.

First you will try from 50 if breaks then 25 if breaks then 13 if breaks then 7 if breaks then 4 if breaks then 2 and so on. This needs highest 6 try.

Here’s a better solution : stuff the truck with pillows leaving enough space for the egg to fit in

i thought he said that he couldn’t get the egg after it’s dropped even if it doesn’t break and i was just so unbelievably lost

This video helps theves 😂

An alternative answer: put a lot of things that cushion the egg so the 100th egg doesn’t break

Y’all are nerds

Put pillows and mattresses in the truck

COMMON SENSE

Can't we do this with 7 times of tries?

Using 50, 25, 12.5, 6.25, 2.125, 1.5625.

Halve the floors, 1st try on 51 floor. If not crashed, go on to 76 floor and if crashed, go down to 26 floor.

Guessing that the egg isn't break on lower floors. 3rd try on 88, 4th 94, 5th 97, 6th 99.

If the 99 floor egg doesn't crash, we have to do 100 floor for the last 7th.

The answer was 14 times, double of my answer. Maybe I missed something but not sure.

The real riddle is why am I helping an egg stealer???

Do I at least get a cut of the egg????

they asked me this question at job interview with google…

It can be done with 7 eggs only:

Egg 1: At (midpoint) 50th floor (Remaining left :50;either below or above this floor)

Egg 2: At (midpoint) 25th (or 75th) floor (Remaining left :25;either below or above this floor)

Egg 3: At (midpoint) 13th (87th) floor (Remaining left :13;either below or above this floor)

Egg 4: At (midpoint) 7th (93rd) floor (Remaining left :7;either below or above this floor)

Egg 5: At (midpoint) 4th (96th) floor (Remaining left :3;either below or above this floor)

Egg 6: At (midpoint) 2nd (98th) floor (Remaining left :1;either below or above this floor)

Egg 7: At 1st or 100th floor for the worst case.

Can’t she just use normal eggs…..?

Wait, can’t the thief just grab the most expensive egg and slide down on the rope holding it?

Logic

And how about, like, grab the egg, put it in a bag, climb down, and drive away?

the title has both "egg" and "yossi", yossi is simillar to yoshi.

is the rarest egg a yoshi egg?

But what if the eggs were softer or harder than the other egg?

The egg gets damaged the more you drop it so..

Wrong

Ted ed, you make great vidoes. Explanation and animations are great. I love to watch these videos. Very interesting and knowledgeable. Can you make a video on HALTING PROBLEM in Turing maching and its proof by contradiction. It will be great.

This is how to do it in 7 tries.. start with the 50th floor

if egg survives, drop it from the 75th floor, otherwise drop another egg from the 25th floor

then +13 floors if the egg survives or -13 floors if the egg breaks

then +6 floors if the egg survives or -6 floors if the egg breaks

then +3 floors if the egg survives or -3 floors if the egg breaks

then +2 floors if the egg survives or -2 floors if the egg breaks

then +1 floors if the egg survives or -1 floors if the egg breaks

Start with 50.

If it breaks, than try 25.

If 25 breaks, steal 10.

If 25 doesn’t break, then toss an egg out of each floor after 25 until you find the floor on which it breaks, steal egg on floor below.

If 50 doesn’t break, try 75.

If 75 breaks, then toss an egg out of each floor after 50 until you find the floor on which it breaks, steal egg on floor below.

If 75 doesn’t break, then toss an egg out of each other floor after 75 until you find the floor on which it breaks, test the floor below it.

If that floor doesn’t break the egg, then steal the egg on that floor.

If that floor does break the egg, then steal the egg on the floor below that.

Easiest way to get the egg:

Eat it

Riddle: gives me a hug

Answer: smacks me in the face

This has nothing to do with the video but I just saw an ad by citi about the totally legitimate "wage gap" but the fact is wemon go into lasser paying jobs then expect to get paid more/equal for lesser work and wonder why they don't get it, now you can argue a point but that will prove mine so… have fun

But wouldn’t the egg be damaged?

13 tries

Step 1: Find out which kind of animal on earth will lay such a big egg. (There's the egg white and yolk inside)

Why not using bisection method ? It will take 7 tries only

Did anybody notice that it said “What’s the least number of tries it would take to guarantee she

FINDthe right floor?”You can do it in 9, if you follow this:

1) (2drops) Drop from 100 and 1, if it breaks at 1 then you have the answer, and if it is fine at 100 you have answer. If neither, then got to next step.

2) (1 drop)If broken at 100, and safe at 1, then drop from floor 50. If it breaks, then you know that it is a floor between 1 and 50, if fine, then it is between 50 and 10.

3) @TED-ED Continue this half pattern until you get to a floor at which the egg will not break. If you get to decimals, round DOWN regardless the decimals. (both 5.1 and 5.9 will round to 5). This in total, will lead to a maximum of 9 drops from start to finish. You are welcome.

Why can’t she through the rope slide down with the egg?

The answer should have been 9 in worst case scenario.([log2(100)]+2)

Now Ted-ed want us to help a theif

Cant she just repel down with the egg?????

what about the guards?

I found a solution where you only need 7 eggs

Or she can just, y'know, be a criminal and attack at night and actually grab a few eggs and run off.

It's easy. Just go to the egg with a guitar image on it, smash it to see it contains a harp, go to the egg with a harp image, etc etc, confirm you have green eyes, insert a blue egg, and drop 5 units of fuel at 8 parsecs.

Well, you can solve the riddle with just 6-7 drops … just keep cutting the number of floors in half while dropping the egg, until you find your sweet spot

The replica eggs are perfectly worthless…. that's why you're selling them

1:00 someone is spying on the thief

Wait but if the robber can slide down

afterdropping the egg in the heist, can she just, you know,slide downwiththe 100th-floor-egg instead of wasting 30 bucks and time?But wouldn't the repeated hits on the replica egg make it more likely to break where the unhitted one wouldn't?

Or you coukd like calculate the energy your egg will gain because of its fall and its resistance and deduce the ideal height

Wouldn't it be much easier to go the 50'th floor, and depending whether the egg breaks or not, to go to the 75'th or to the 25'th? Then divide by two each interval until it reaches to the desired floor?

Step one: cushion the van

Step two: go to floor 100

Step three: drop the egg

Step four: sell the egg.

I would start a trend.

Like a drop the egg trend where you go to this building and see who can get the highest story drop without breaking. You wouldn’t become a suspect because everyone is doing it and the security won’t stop it because the souvenir shop profits are at an all time high.

Can you solve a riddle?

no. no I cantJust start with fifty then then use higher or lower narrowing your brain is too small

Why do I need to know this again?

Take the egg with you as you repel down to the truk

Imagine if D the top floor egg had so many Nokia 3310 surrounded basically survive anything and cracked the truck

she thiccWouldn't it wear out, or it may be a plastic or different material?

Why dont you just put a pillow where the egg is going to land?

Duh its simple just put a pillow then go for the 100th egg

why can't she just hold onto the egg with one arm as she propels down instead of dropping it?

Each drop will weaken the structural durability of the egg.

In other words, the egg will be more sturdy at the first drop than the 10th lol

did i misunderstand this riddle or something? if we start at 50 then depending on whether it breaks or not we add or subtract by 25 then repeat for 13 and then 7 then 4 then 2 then 1 this takes care of worst case scenario

Wait

Why would there be an EGG museum?

Like

They're all pretty and stuff

BUY WHY???

Just do research

me an intellectual: fills truck with soft pillows and materials

If it was me here I would just give up.

Thank youuu Teded ❤️❤️❤️❤️❤️

A binary search would be a better approach – i.e. throw the first egg from floor 50, if it breaks throw the next one from floor 25, if it does not break there throw the next one from floor 37 and so on.. this strategy only takes log2(100) ~ 7

ah yes, with my priceless egg, I will make the best omelette everBest solution

1.Ask bank for money

2. Buy helicopter with money

3. Steal egg on top floor

Or

Do one of those science experiment things

-Parachute

-Straw armor

-Egg in the middle of a balloon

-Egg in middle of popcorn bag

-Use drone

I could easily be done at max within 7>

Use Feather falling X boots, a bed and just to be safe a totem of undying

Why are we helping the thief?????

This answer is wrong

i don't mean to help a criminal but…

What you egg?

he stabs himYou are training us so well

To Steal😆

Instructions unclear, made an omelet.

I was close, nice

Bring a backpack, steal the egg, get out

Me: “ Brain POWER”

Why are you helping a thief?

The way these riddles are worded is nonsensical. It was never mentioned that you could drop the same egg from multiple floors until it broke!

Did anyone else realise we are helping a thief?