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# bonanova

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• Birthday November 3

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1. ## Make Three 7's equal 10

Using the number 0 or extra 2's does not fit the allowed operations. Only Sqrt(4) + 4 + 4 = 10 seems allowable.
2. ## Finding a fiver

You are given an exhaustive 5-letter English word list. How would you determine the probability that 7 randomly chosen letters form at least one of those words? Or the expected number of words they form?

4. ## Gift wrapping the Puzzle blocks

So the problem is to fill a cubical box of side S with convex blocks having integral-length edges {L W H} whose values are taken without replacement from the set { 1, 2, 3, 4, 5, 6, ..., S-2, S-1, S } ? Or must they be taken from the set that excludes S? That is, can one of the blocks have an edge length equal to S?

Assuming you meant things of value (perhaps coins?) into the boxes, then ...
6. ## Gift wrapping the Puzzle blocks

The LxWxH block dimension seems to rule out Since OP does not it seems the smallest box would be But that requirement probably was intended. Also, I don't see that unique coloring imposes any limits beyond that of unique dimensions.
7. ## The JayCees

Jane, Janice, Jack, Jasper, and Jim are five high-school chums. Their last names are, in some order, Carter, Carver, Clark, Clayton, and Cramer. What are their full names? Here are some clues. Jasper's mom is deceased. In deference to an influential family member, the Claytons agreed that if they ever had a daughter they would name her Janice. Jane's parents have never met Jack's parents. The Cramer and Carter children have been teammates on several of the school's athletic teams. When he heard that Carver was going to out of town on the night of the school's Father and Son banquet, Cramer called Mrs. Carver and offered to "adopt" her son for the evening. But Jack's father had already asked him to go. The Clarks and Carters, staunch Republicans who are very good friends, were delighted when their children began dating each other.
8. ## Once more with the Maiden

@plasmid My bad. It's not polite to post a puzzle and then go dark for two months. Apologies. In the first version there was no acceleration cost for either contestant. They both could stop on a dime, turn, and resume at full speed instantly. So here I've added a cost for angular change of velocity (for the boat only) but none for linear acceleration. Before I finished my solution my hard drive fried. I replaced my computer but I lost my work. I'll share how far I got and maybe we can finish this off collaboratively.
9. ## Photochromism 326 BC

I sort of hesitate to relay a tongue in cheek report I read a while back that photochromic materials are not of recent discovery, but were actually known back in the time of Alexander the Great. A black substance could be ground into powder and dissolved in water. Alexander’s troops would soak strips of cloth torn from their togas in this solution and tie them around their wrists. As the sun rose, traversed the sky and then set, the treated cloth would change color, and by glancing at them his men could tell the approximate time of day. They called it Alexander’s Rag Time Band.
10. ## Swapped numbers

In each case is there a swap? Or are there longer cycles as well?
11. ## Diameters

Hi @CynPyn and welcome to the Den. Let's accept from this that Rmax is the unit diameter circle. Now imagine a rectangle with unit diameter (diagonal has length 1.) That can be made to fit into Rmax . The question is does every unit-diameter region into Rmax ?
12. ## Diameters

The diameter of a closed, topologically bounded region of the plane is the greatest distance between two points in the region. Example: the diameter of a rectangle is the length of its diagonal. Of all the regions whose diameter equals 1, one of them, call it Rmax, encloses the largest area. Can you prove, or disprove, that Rmax also encloses all other regions of diameter 1? That is, that all other regions of diameter 1 can be made to fit inside Rmax?
13. ## Once more with the Maiden

Previously, Maiden’s boat could change its heading instantaneously. Ogre’s heading could change only by virtue of following a circular path along the shore at his current speed. His rotational speed was thus far from infinite, and perhaps that disadvantage was unfair. So in this final puzzle iteration we’ll limit the boat’s linear speed to be f times that of Ogre, as before, but now we’ll also limit the boat’s angular speed to be never greater than g times Ogre’s top angular speed. A moment’s thought tells us that unless g is greater than unity the boat’s best strategy is to run at full speed from the center to the shore, keeping its initial bearing, no matter where on the shore Ogre initially stands. That is, never to turn the boat. That sucks for Maiden (e.g., she loses if Ogre initially stands at the boat's initial heading) and it sucks as a puzzle. So we’ll say the boat can change heading faster than Ogre can. For clarity we’ll set g = 2. We’ll implement that limit by giving the boat’s motor three discrete settings that can be switched instantly an unlimited number of times: clockwise (CW), full speed ahead (FSA), and counterclockwise (CCW.) In the two turning modes the boat turns but maintains its position; in FSA mode it moves forward but does not turn. Boat’s path is thus a succession of arbitrarily short line segments joined at angles of Maiden's choosing, with the time cost of the angle depending on its size. If the boat starts in the middle of the lake, how large must f now be for Maiden to escape? Edit: Extra credit (tough): If Ogre's top speed is 1 lake-radius per minute, and Maiden chooses the boat's initial heading at the center, what's her shortest time safely to shore?
14. ## Ten Islands

Yes it is possible. The Triborough Bridge in New York connects Manhattan, the Bronx and' Queens.
15. ## Kill Bill redux

Hmmm. I hadn't considered that. Is there a different solution if the murderer did not own the murder weapon?
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