13 replies to this topic

[Dempsey Collins]

Drop your first egg from the following floors until (or if) it breaks:
6th, 12, 18, 24, 30, 35

Worst case comes if the egg breaks on either the 30th or 35th floor.

If it breaks on the 30th floor, then take the second egg and start at 26 and go through 28, for a total of 8. You can skip 25, since you know 24 worked. No need to go past 28 because you know 30 didn't work.

If it breaks on the 35th floor, then take the second egg and start at 32 and go to 33, for a total of 8.

All other breaks result in less than 8.

Good puzzle. Thanks.

This does not work. Looking at your 35th floor example, you test the 35th floor on your 6th attempt. If the egg breaks there, then it must be either 31,32,33 or 34.

If you use your 2nd egg to start at 32, you're not attempting to break the egg at 31. Its possible that if you were to try it at 31, it would still break and the 30th floor would be the highest.

[Riddle Master Zack]

Have to agree with the last post - how would you know if it was floor 5 or 6?

Here's the real answer

Spoiler for

If you throw an egg out of the 36th floor with the pointy bit at the front and a slight spin, it will end up hitting the ground 'tip' first. The egg won't break as long as that happens - go try it!

Thats only If Gravity wasn't pulling it down over 100 miles per hour, praying that kinetic laws will allow it to stay on the sidewalk without breaking, and then hoping that it was spinning?

[flamedudex]

[spoiler]
8 drops.
Drop from 8th, 15th, 20th, 26th, 30th, 33rd, 35th and finally the 36th (to see if it even breaks at the 36th) floors
Whenever the first egg breaks, start dropping second egg from the next lower floor. The max number of drops will be 8
[/spoiler ]

Still having problems with the spoiler!

shouldnt the numbers be 8, 15, 21, 26, 30, 33, 35, 36?

if it was 20th, then if the egg didnt break on the 25th level, you wouldnt know until you tried 9 times.

8 15 20 26 21 22 23 24 25

Edited by flamedudex, 21 July 2009 - 06:43 PM.

[jnatkins]

You can skip 25, since you know 24 worked.

?????
what kind of logic is this?

The Answer is 8.. but here's why..

Spoiler for The Real Soultion

You can determine the answer logically by working backwards incrementing the spacing between drops by 1 floor each time until you reach the ground.

Drop final egg on 36th floor -1=35-2=33-3=30-4=26-5=21-6=15-7=8-8=0 Therefore start on the 8th floor.. If the egg breaks start at floor 1 and work your way up until you get to 7.. if you do the max drops would be 8.. if the egg does not break on 8 then move up to 15.. If the egg breaks go to the next floor above the highest floor that didn't break and work your way up.. rinse and repeat

The formula x(x+1)=yz y=the number of eggs, z=number of floors, solve for x (the number of drops)... therefore x(x+1)=2*36... x(x+1)=72... 8*9=72.. x=8