- You are given eight coins and told that one of them is counterfeit. The counterfeit one is slightly heavier than the other seven. Otherwise, the coins look identical. Using a simple balance scale, can you determine which coin is counterfeit using the scale only twice?
First weigh three coins against three others. If the weights are equal, weigh the remaining two against each other. The heavier one is the counterfeit. If one of the groups of three is heavier, weigh two of those coins against each other. If one is heavier, it's the counterfeit. If they have equal weight, the third coin is the counterfeit.
- Three people picked 65 apples altogether. At the first tree they each picked the same number of apples. At the second tree they each picked 3 times as many as they picked at the first tree. When they finished at the third tree, the group had 5 times as many apples as they had when they started at that tree. At the fourth tree the group picked just 5 apples. How many apples did each person pick at the first tree?
- A man and his son had a terrible car accident and were rushed to the hospital. The man died on the way, but the son was still alive and a surgeon was called in to operate. However, the surgeon saw the young boy and said, "I can't operate on this boy. He's my son."
How is this possible?
The surgeon was his mother.
- You are a cook in a remote area with no clocks or other way of keeping time other than a four minute sandglass timer and a seven minute sandglass timer. (The kind you turn over - hourglass shaped) You do have a stove, however, with water in a pot already boiling. Somebody asks you for a nine-minute egg, and you know this person is a perfectionist and will be able to tell if you undercook or overcook the eggs by even a few seconds. What is the least amount of time it will take to prepare the egg? And how will you prepare it so that it is neither undercooked nor overcooked?
The answer is 9 minutes. First, flip both hourglasses over and drop the egg into the water. When the four minute timer runs out, flip it again. When the seven minute timer runs out, flip it over. The egg has been cooking seven minutes. Now when the four minute timer runs out again (after eight minutes) flip the seven minute timer back over. Since the seven minute timer has been running only a minute between flips, there's a minute worth of sand left. And when that minute runs out, the egg will have been cooking for exactly nine minutes.
- What is it?
The Pope has it but he does not use it.
Your father has it but your mother uses it.
Nuns do not need it.
Arnold Schwarzenegger has a big one,
Michael J. Fox’s is quite small.
What is it?
- An Arab sheikh tells his two sons to race their camels to a distant city to see who will inherit his fortune. The one whose camel is slower will win. The brothers, after wandering aimlessly for days, ask a wise man for advise. After hearing the advice they jump on the camels and race as fast as they can to the city. What does the wise man say?
The wise man tells them to switch camels.
- 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.
- A man is looking at a picture of a man on the wall and states: Brothers and sisters I have none, but this man's father is my father's son. Who is the man in the picture in relation to the man looking at the picture?
The man in the picture is his son. Since he doesn't have any brothers or sisters, the statement my father's son is himself. A shortened version would be this man's father is myself, so he is the father of the man in the picture.
- During WWII, there was a bridge connecting Germany and Switzerland, and on the German side, there was a sentry tower with a guard in it. He would come out every three minutes to check on the bridge, and he had orders to turn back anyone who tried to get into Germany, and shoot anyone trying to escape without a pass. There was a woman who desperately needed to get into Switzerland, and she knew she didn't have time to get a pass. It would take her at least six minutes to cross the bridge, but she managed to do it. How?
She walked on the bridge towards Switzerland for 3 minutes and just as the guard was about to come out, she turned around walking back to Germany. The guard saw her and asked for her pass but she didn't have one and was sent back (or what the guard thought was back) to Switzerland. In her case it was the very country she wanted to go to.
- What seven-letter word has hundreds of letters in it?