Brain Teasers / Games

Stone-Washed Genes

Both of my parents have brown eyes, as do I. My brother and my wife have blue eyes. Using the simple brown-blue model (two genes; a brown gene dominates blue gene), what are the chances of my first child having blue eyes?

Shooting Star

Henry and Gretchen plan on sitting outside to look for shooting stars. They know from experience that if they watch for an hour, they will have a 90% chance of seeing a shooting star. It is a chilly night, though, so Gretchen says, "Let's only stay out for 10 minutes."

Henry says, "I was really hoping to see a shooting star tonight. If we are only out for 10 minutes, we will only have a 15% chance."

Gretchen replies, "Not true. We have a better chance than that."

Is Gretchen right? If so, what is the probability that they see a shooting star?

Train Problem

Elliot the detective heard the news of a double murder that occured on a train. The driver and the conductor were on the opposite sides of the train, but both were shot at the same time, reported a policeman who was at the center of the train at the time. The policeman had heard both gunshots at the same time. The train was travelling 150 kilometers per hour. Elliot immediately realized that the driver and the conductor were not killed at the same time. How is it so?

To Grandma's House

You are on your way to visit your Grandma, who lives at the end of the valley. It's her birthday, and you want to give her the cakes you've made.

Between your house and her house, you have to cross 7 bridges, and as it goes in the land of make believe, there is a troll under every bridge! Each troll, quite rightly, insists that you pay a troll toll. Before you can cross their bridge, you have to give them half of the cakes you are carrying, but as they are kind trolls, they each give you back a single cake.

How many cakes do you have to leave home with to make sure that you arrive at Grandma's with exactly 2 cakes?

More Oxymorons

The five phrases below can be reworded into oxymorons. Can you figure out what they are?

Example: Initial facsimile = original copy

1) discovered lost
2) bigger part
3) sugary sour
4) sad humor
5) solitary in company