bonanova

Would a propeller and a jet perform the same in space? If not, does that change any of your statements?

Resurrecting a discussion ... Regarding wiping the numbers from the balls.. You see immediately that each operation puts a ball into B and another into C [or discards it] If you want the identity of a ball in B after it's all over, simply place a mark on the first ball to get into B. There's your identified ball. Now to your contentions: You contend two things, without proof. If you wipe the numbers off the balls they do not constitute a set. You cannot select randomly from an infinite number of objects. Let's see if they make sense. I have 15 balls. 5 are red, 5 are blue, 5 have no identifying marks. The 15 balls do not constitute a set because they are not numbered. Or perhaps the 5 red balls are a set because they are red and the 5 blue balls are a set because they are blue. But the 5 unmarked balls are not a set because they are unmarked. Interesting. If the numbers are erased consider that bin A is an infinitely long trough, and the balls are ordered, left to right. Now they are distinguishable, so even your criterion makes them a set. Take the first two and put one of them into B [and put a dot on it] and the other into C [or discard it]. Repeat. That ball with a dot is the identity of one ball that is in bin B, as requested. You cant choose randomly from an infinite set. From the countably infinite set of rational numbers on the interval [3,4) i choose the number 3.14 Prove that that choice was not random.

Already posted. Do a search [unusual +paragraph] to see whether a puzzle has already been posted to this forum. Locked. - bn

Already posted. Use search [bear +color] to see whether the puzzle is new to this forum. Locked. - bn

Tossing a couple Excedrin to SR.

Interesting. But let me guess: your engineering major is not rocket science. [1] I think we all agree the wheels are a red herring, and so is the treadmill. Skis on snow, or pontoons on water, wouldn't change things. [4] And lift is provided by airflow over [and under] the wings, courtesy of Bernoulli's principle. [Wings don't provide lift in space, e.g.] So it is all about air speed. [3] If props "push against air" to provide thrust, they wouldn't work in space. OK. They don't. We agree on everything, so far. [see my answer to Martini's original statement of this puzzle.] But ... [3] But if jets "push against the air" they wouldn't work in space, either. Ooops.

Which is why I removed them. If you want to give a meaningful clue, how about: the nth word has m letters. Where you get to choose n. I'd vote for n=1, but that might be too helpful.

No correct answers so far.

Ah, woon beat me.

Triangle ABC is isosceles. Find angle x. Do not assume the figure is drawn to scale. Do not use the law of sines. Use simple geometric reasoning, like Isosceles triangles have two equal angles and sides. The angles of a triangle sum to 180 degrees. Things like that. Have fun.

CR is clearly correct. And timely. But I really liked CL's answer. Good one.

The following statement may or may not be false. The previous statement definitely is false. After you figure that out, note that the OP limits the mathematical operators that you can use to "+,-,*,/." Contrarily, parens are just signposts. Yes, they can affect the calculation, but intrinsically, they're not ops. For example 5+6 = 11 = 5+(6) = (5)+6 = (5) + (6) = (5 + 6) = ((5) + 6) = ...

I certainly hope so ...

Agree totally. By "take it from there" I meant "finish what I can't finish", not " the rest is easy."

Switching gives you a 2/3 chance for the car. Therefore, sticking gives you a 2/3 chance for the goat. I'm not sure how you try to pick a goat while aiming for a Jaguar, but it's your decision: decide what you want, and take the winning strategy. By the way, there are a number of places on the web where the whole scenario is simulated. You can play the thing all day long and discover for yourself what happens. If you're ever in town and have some extra cash, I'll show you myself, even.

bn frantically searches for the DELETE POST button, but after a moment's thought decides not to use it.

Alex slides a cold one down the bar to clueless.

Take it from there.

Not the best solution posted, but a different approach. Two rolls with possibility of re-rolls needed: expected rolls = 2.54.