My family sings Christmas carols at the hospital where my wife works. We do this every year and since we started, have not missed a single year. The next time we do this will be the 18th consecutive Christmas. My 15 year old daughter has been every time.
She was born in March 1999 so the first year she came was December 1999 (before her 1st birthday). Her first time was when she was 0, second time when she was 1, third time when she was 2, etc…
Now that she is 15, she has been 16 times. Oh and of course she was also present in December 1998 in her mum’s belly, due to be born the next March.
So, a total of 17 times and next time will be the 18th.
Thanks to Michael for submitting this real-life brain teaser about his family.
Walking down the street one day, I met a woman strolling with her daughter. “What a lovely child,” I remarked. “In fact, I have a younger child as well,” she replied.
What is the probability that both of her children are girls?
1/2 probability. This has been know to cause raging debates and is known as one of the variations of the Boy or Girl paradox. This variation is more straightforward because knowing the position of the child leaves only two possibilities – the other child is a boy or a girl, each of which have a 1/2 probability.
The first two letters of this English word refer to a male, the first three refer to a female, the first four to a great man and the whole word is a great woman.
You have fifty quarters on the table in front of you. You are blindfolded and cannot discern whether a coin is heads up or tails up by feeling it. You are told that x coins are heads up, where 0 < x < 50. You are asked to separate the coins into two piles in such a way that the number of heads up coins in both piles is the same at the end. You may flip any coin over as many times as you want.