An 18-wheeler is crossing a 4 kilometer bridge that can only support 10,000 kilograms and that’s exactly how much the rig weighs. Halfway across the bridge a 30 gram sparrow lands on the cab, but the bridge doesn’t collapse. Why not?
Since the bridge is 4 kilometers long, the halfway point would be 2 kilometers. The 18-wheeler would have used much more than 30g of fuel to drive 2 kilometers.
Imagine an HIV test that is 95% accurate (false positive rate of 5%) and around 2% of the tested population is infected with HIV. What is the probability that you actually have HIV when your test comes back positive?
Kings and lords and christians raised them
Since they stand for higher powers
Yet few of them would stand, I’m certain,
If women ruled this world of ours.
Suppose you have twelve eggs and a balance scale. All of the eggs are identical except for one whose only difference is its weight. Using the scale only three times, determine which egg is the odd egg out and whether it is heavier or lighter than the other eggs.
Weigh four against four. If they’re equal, weigh three of them against three you haven’t weighed. If they balance too, weigh the last remaining egg against any of the others to see if it is lighter or heavier. If the three suspects are heavier, weigh one of them against another and the one that goes down is it. If they balance the remaining suspect is heavy. Use the same process if they’re lighter. If the initial four vs four don’t balance, weigh two heavy eggs and a light egg against one heavy egg, one light one and a known normal egg. If they balance weigh the remaining two light eggs against each other. If they balance the unweighed heavy egg is the odd one out. If the side with two heavy eggs goes down weigh them against each other. If they balance it is the light egg on the other side. If the other side goes down it is either because of one heavy egg on that side or because the one light egg on the other side is lighter than the rest. Weigh one of them against a known normal egg to determine which is true.
A one way street sign. It tells you the correct way to go, is black and white (in the United States), going the wrong way can get you a citation and the sign only has two words on it.
1. How do you put a giraffe into a refrigerator?
2. How do you put an elephant into a refrigerator?
3. The Lion King is hosting an animal conference. All the animals attend except one. Which animal doesn’t attend?
4. There is a river you must cross but it is used by crocodiles and you don’t have a boat. How can you cross safely?
1. Open the refrigerator, put the giraffe in and close the door. It’s not complicated.
2. Open the refrigerator, take out the giraffe, then put in the elephant and close the door.
3. The elephant. He’s still in the refrigerator. After all, you just put him there.
4. Jump into the river and swim across. The crocodiles are at the Lion King’s animal meeting.
I admit, this is not a typical brain teaser, but it amused me.
It cannot be seen, it cannot be felt,
Cannot be heard, cannot be smelt,
Lies behind stars and under hills,
And empty holes it fills.
Comes first follows after,
Ends life kills laughter.
