A fisherman rowing his boat on a very small lake throws his anchor into the water. Does the water level of the lake rise, fall, or stay the same?

A farmer has 3 square fields shown above, each containing 18, 20, and 26 acres. In order to get a fence around his property, he bought the 4 intervening triangular fields.

Lucy was born on a sunny Sunday in Hong Kong and celebrated her 7th birthday party on a rainy Sunday in Macau. How old was she in 1996?

A list of people who have solved so far:

Hard: Dan, Shawn, michaelC, LaDana,

If the earth should suffer an apocalypse on the first day of a new century, can you say what the chances are that it will happen on a Sunday?

Here’s a neat little math brainteaser:

Zenith let me know of this excellent challenge.  Looks like it should be easy, but it’s not:

What’s the next sequence in this set?

1

11

21

1211

111221

you may submit your answers below in the comment section; will unmask in several days, thanks.

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We’ve been working hard on getting the Smartkit Forums ready. Come Monday, we’ll officially open them up. You’ll be able to:

• post some of your own puzzles
• play forum games
• pick the brains of other smartkit members

OK, here’s Thursday’s challenge. Can you figure it out?

Jake says to his buddy Chirag, "I’ll bet you 1/2 the money in my wallet on the toss of a penny- heads I win, tails I lose."

Farmer Thomas sold a pair of cows for $210. On one he made 10%, and on the other he lost 10%- earning just 5% on his transaction. What did the cows originally cost him?

Think you have the right answer? Enter it as a ‘comment’ in the section below. Submissions will be unmasked in several days, thanks.

Saw some comments show up recently on our first scale balance puzzle (hard!), which reminded me how long its been since we put one of these up. With that in mind:

How many triangles are need to balance scale 3?

In a solar system far, far away, 2 planets are exactly in line with their sun (as above).

Icerix, the colder planet farther away, takes 350 days to obrit the sun.

Cetacearth, the watery planet closer to the sun, only takes 100.

Assuming the orbits are in the same plane, in how many days will the 2 planets next be in line with their sun again?

What is the area of white (without the semi-circle moon shadows)?

Each square is one square inch.

How do you prove it? (pi=3.142)

Created for Smart-Kit by Forrest Frantz

For the teachers following, this definitely makes for a

"My wife’s age", said John, "can be found by reversing the figures of my own age. She is my senior, and the difference between our ages is 1/11 of their sum".

How old is John?

[submit your answers in the comment section below, and we'll unmask them in 1 day]

Mother Thrifty and her daughter Dollie each drive 30 ducks to the market. Mother Thrifty is eager for a trade, and hurries on with her 30, and reaches the market early when ducks are in demand. She sells two for one dollar; but Dollie dawdles along the road, and when she arrives the market is supplied so she only receives one dollar for every three.

How many minutes is it until 6 am if 50 minutes ago it was 4x as many minutes past 3 am?

[Will unmask submitted answers in 1 day]

"These are all the hens we have left", said the butcher to the 3 women who were shopping in the market. "Together they weigh 20 pounds, and the little bird sells for 2 cents a pound more than the big bird."

Mrs. Davis bought the little one for 82 cents, and Mrs. Miller paid 2 dollars and 96 cents for the big hen.

An Innkeeper purchased an odd number of wine kegs, and one keg of beer. These are shown in the picture above. The Innkeeper then sold an amount of the wine to one woman and twice this amount to another, but kept the beer to herself.

Can you figure out which keg contains the beer? (the kegs were sold just as they were purchased, without manipulating the contents)

Can you figure out what the missing number is?

for this math puzzle, will unmask any submitted answers in a day or 2.

A girl wanted to play on the seesaw. However, she couldn’t find another child to play with her, so she tied some books to one end of the plank to balance her weight at the other.

She just balanced against 16 books, when these were fixed to the short end of the plank, but if she fixed them to the long end of the plank, she only needed 11 as balance.

How can a window, having a height equal to its width, be made twice as large without increasing its height or width?

(will unmask any submitted answers to this puzzle in 24-48 hrs, thanks)

Two children went to town to sell their eggs, one had more in her basket than the other; the one who had the most said to the other, “Give me one of your eggs, and then I shall have double the number you have.”-”No”, said the other; “give me one of yours, and then we shall have equal”.

ok, for those who thought the last couple brain teasers were too easy, let’s kick it up a notch