50% chance of 0 girls, 1 boy
25% chance of 1 girl, 1 boy
12.5% chance of 2 girls, 1 boy
6.25% chance of 3 girls, 1 boy

There will always a be 1 boy in there. But it makes more sense to think about it the other way. Every birth is just a normal 50%-50%. Doesn’t matter when any particular family decides to stop.

I am totally confused, although I guess the probability numbers do add up equally for both sexes. My impression was that as only people with girls and no boys continue breeding, there would be more girls. Then I threw a coin 100 times and was dismayed to get the equivalent of 97 boys and 86 girls where heads symbolized a boy and tails a girl.

Solution #1: The shape made is a regular hexagon.

Solution #2: It is impossible. Consider the colours of the squares of the chessboard. There are 32 white squares, and 30 black squares. Each domino will cover one black and one white square. No matter how you do things, the last domino wil have to cover two white squares, which is impossible.

Solution #3: 140 km. It takes 2 hours for the trucks to collide. So the fly is flying for two hours at 70 km/h. He flies 140 km. In a test, university students took longer to answer this than 12 year olds.

Solution #4: 1 weighing. Take one coin from the first pile, two from the second and 10 from the last pile. You have 55 coins on the scale, which would weigh 550g if all coins were real. If it weighs 1g more, then the 1st pile is counterfeit, 2g more the second etc.

Solution #5: 17 minutes: 1 and 2 go across – 2 mins. 1 comes back – 3 mins. 5 and 10 go across – 13 mins. 2 comes back – 15 mine. 1 and 2 go across – 17 minutes

Solution #6: First, put on both condoms together, and ‘do’ A. Then, take off the top condom, and do B. Finally, turn the removed condom inside-out, put it back on over the first, and do C. This is the only way to do it.

Solution #7: 0. The 24th term in the expansion is (x-x) = 0. Anything multiplied by zero is zero. Sorry.

Solution #8: A has a black hat. As far as I can see, it is not possible to determine the hats of the other two. When C says he doesn’t know, this must mean that it is impossible for both A and B to have white hats. Otherwise, C would know he had a black hat. Thus, when B say he doesn’t know, A must have a black hat. If B saw that A had a white hat, he would know he had a black hat. So, A can determine that he is wearing a black hat.

Solution #9: The question is again completely misleading. Only twenty-seven dollars were paid by the three men. 25 went to the hotel and 2 to the receptionist. Trying to add to get back to 30 is simply nonsensical.

Solution #10: 1:1, as in any normal town. Every birth is natural, and each child still has a 50/50 chance of being a boy or a girl. No babies are being killed or anything. It wouldn’t matter if they stopped after having a child with blue eyes, a child with 7 toes etc. Alternatively, you could sum the infinite series of probabilities. Each family has one boy. There is a 50% chance of no girls, and 25% chance of 1 girl, a 12.5% chance of 2 girl etc.

waiting (impatiently) for the answers.

Oh and I think the answer to 3 is no where. When the train and the fly collide they are not moving. If you assume squashed to me the collision then no where is the answer. Anyway, I shall not try and reinvent anything.

A, B, C are rowed up: b is looking at a’s back, c is looking at a & b’s back, a is looking at the wall

c can see a and b, b sees a, a sees no one

c must see 1 black hat and 1 white as he’s not able to make a guess. He is therefore be wearing black

b hears nothing from c but can see a is wearing black. He is in fact wearing white

a knows he’s wearing black and states this.

When we finally get to meet, I’m going to NOT buy you a pint!

Here’s one for you:

2 doors — one leads to life, the other, death. Problem: they are not marked *life* or *death*.

Both doors have a guard. You may ask one guard one question to make your selection.

Further problem: one guard tells the truth, the other lies {no doubt the manager!}. There is no discernible difference between the guards.

What one question could ask either guard to ensure you make the right choice?

Grrrrrrrrr! What a way to start Friday!!!!!!!