Fun Mathy Type Riddles

[FatAndFaithless]

Just for the bucket one since I love those ones.

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  Fill the 4 gal, dump it into the 7 gal - leaving 3 gal empty space.
Fill the 4 gal again, dump it into the 7 gal until it is full - taking up the 3 gal of empty space and leaving 1 gal in the smaller bucket.
Empty the 7 gal on the floor.
Put the 1 gal from the smaller bucket into the big bucket.
Fill the 4 gal again, dump it into the big bucket to combine it with the 1 gal to make 5 gal.

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And the ball one:

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Ball drops 40ft *touch ground 1* -> total traveled = 40 ft
Ball goes up 20ft, then down 20ft *touch ground 2* -> total traveled = 40 + 20 +20 = 80
Ball goes up 10ft, then down 10 ft *touch ground 3* -> total traveled = 80 +10 +10 = 100
Ball goes up 5ft, then down 5ft *touch ground 4* -> total travel = 100 + 5 + 5 = 110 ft

That one was simple enough that I'm almost certain I missed something in the question.

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Yep, I think the ball problem only catches anyone if they forget to count the upward bounce between each drop.

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  I scribbled the bolt/tray one - got the tray weighing 340 grams

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for the toothpick one, if you don't count 'moving' as 'removing' the you could remove the two middle vertical toothpicks, and move one of the horizontal ones to become the new vertical for a small square in the corner of the larger square to end up two squares... and I have no idea how to make a picture of that with typing.

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