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.
Mario is testing out a new car at the racetrack. His grandmother took it for a mile lap and averaged 30mph. How fast does Mario have to drive in the second lap to average 60mph for the two miles?
90mph is an alluring answer, but it’s impossible. At 90mph the second lap would take 40 seconds. If Grannie’s first lap at 30mph took 2 minutes, traveling 2 miles in 2 minutes and 40 seconds is an average speed of 45mph. Traveling an average speed of 60mph for 2 miles would take 2 minutes and since the grandma’s lap took all of those 2 minutes, even if Mario could break the sound barrier he wouldn’t be able to average 60mph.
A bed. The foot of the bed can’t walk and the head of the bed can’t talk. It’s probably a good thing that beds can’t walk and talk. Just think of where they’d go and what they’d say…