The diamond problem again. (I'm getting more 'brain-teasing' out of deconstructing the puzzle that I did from the puzzle itself)
"If three of the boards are floated in the acid."
Unfortunately, the lake is not water but
highly concentrated acid
, the result of ignoring paranoid environmentalists.
This is of cause part of the problem with words. Whilst, I agree with you it would be impossible to hold it out over the acid. . Adrian's excellent answer would still apply if the last plank was held vertically, and allowed to fall to the island with only say a foot to stop its bounce.
However, as I seems slightly unlikely that we will ever find ourselves in a similar situation perhaps we will never know for sure. :wink:
The pyramids.
The block moves about 4 cubits, or a little over two yards. If you were thrown off by this deceptively simple problem, you probably forgot that while a point on the circumference of the roller moves two cubits relative to a point on the ground per rotation, that point on the roller also moves two cubits relative to a point on the block.
Five (5) is the maximum
You can arrange up to five quarters in a way that each quarter touches every other quarter. Starting with one horizontal quarter as the base, arrange two additional quarters to form a small "tent" over the first, resting lightly on top of it. The tricky part is adding two more. These two must touch each other at the tip, with their bases just barely filling the gap left by the others.
Relative wrote "
"And I don't understand that self-referencing prose.."
Nor do I. Too what do refer? Are you by chance, a relative of Adrian?
Rope around the world.
The circumference of a circle is 2 x pi x r, where r is the radius of the circle. If you want a rope that is one yard above the ground, this radius is larger by one yard. Let R be this new radius. So R = r + 1.
Let x be the amount of extra rope required by the eccentric's rival. So:
x = (2 x pi x (r + 1)) - (2 x pi x r) x = (2 x pi x r) + (2 x pi) - (2 x pi x r) x = 2 x pi
So x is about 6.2832 yards.
Note that this answer does not depend on the radius of the circle. If the eccentric and his rival were attempting to tie up a baseball rather than the earth, the amount of additional required rope would be the same amount.
Relative quote "Here's another: one guy decided not to make it elevated 1 yard all around, just support it with a stick 1 meter high. What now?"
Very little difference.
I leave you with;
You've angered the spirit of Halloween by failing to revere the Great Pumpkin, and now a curse has befallen you. On the walkway to your house is a Ward of Seven Jack O' Lanterns arranged in a circle. If midnight comes and any of the seven are still lit, a dark reaper and seven dark horses with seven dark riders shall visit thy abode. They shall surround thy domicile and circle it seven times seven times. And the seven riders having circled thy dwelling seven times seven times, they shall proceed with the throwing of the eggs and the cream of shaving. And come morn there will be a great mess to be reckoned with. Verily.
Therefore, you had better get those lanterns out.
You quickly discover something odd about these lanterns. When you blow out the first one, the lanterns on either side extinguish as well! But there's more- if you blow out a lantern adjacent to one that is extinguished, the extinguished one(s) will relight. It seems that blowing on any lantern will change the state of three- the one you blew on, and its two neighbours. Finally, you can blow on an extinguished lantern and it will relight, and its two neighbours will extinguish/ignite.
After a frustrating exercise of playing "Whack-A-Mole" with the lanterns, you find yourself back where you started, with all seven lit. Being the excellent puzzler you are, you sit down and examine the puzzle logically. However, be quick, hoof steps approach.