Note: This riddle must be done IN YOUR HEAD ONLY and NOT using paper and a pen.
Take 1000 and add 40 to it.
Now add another 1000.
Now add 30.
Now add 20.
Now add another 1000.
Now add 10.
What is the total?
The answer is 4100, check it out on a calculator. Did you think it was 5000? Most people add the 100 as 1000 by mistake.
This teaser is based on a weird but true story from a few years ago. A complaint was received by the president of a major car company: "This is the fourth time I have written you, and I don't blame you for not answering me because I must sound crazy, but it is a fact that we have a tradition in our family of having ice cream for dessert after dinner each night. Every night after we've eaten, the family votes on which flavor of ice cream we should have and I drive down to the store to get it. I recently purchased a new Pantsmobile from your company and since then my trips to the store have created a problem. You see, every time I buy vanilla ice cream my car won't start. If I get any other kind of ice cream the car starts just fine. I want you to know I'm serious about this question, no matter how silly it sounds: 'What is there about a Pantsmobile that makes it not start when I get vanilla ice cream, and easy to start whenever I get any other kind?'"
The Pantsmobile company President was understandably skeptical about the letter, but he sent an engineer to check it out anyway. He had arranged to meet the man just after dinner time, so the two hopped into the car and drove to the grocery store. The man bought vanilla ice cream that night and, sure enough, after they came back to the car it wouldn't start for several minutes. The engineer returned for three more nights. The first night, the man got chocolate. The car started right away. The second night, he got strawberry and again the car started right up. The third night he bought vanilla and the car failed to start. There was a logical reason why the man's car wouldn't start when he bought vanilla ice cream. What was it?
The man lived in an extremely hot city, and this took place during the summer. Also, the layout of the grocery store was such that it took the man less time to buy vanilla ice cream.
Vanilla ice cream was the most popular flavor and was on display in a little case near the express check out, while the other flavors were in the back of the store and took more time to select and check out. This mattered because the man's car was experiencing vapor lock, which is excess heat boiling the fuel in the fuel line and the resulting air bubbles blocking the flow of fuel until the car has enough time to cool.. When the car was running there was enough pressure to move the bubbles along, but not when the car was trying to start.
Three ants are sitting at the three corners of an equilateral triangle. Each ant starts randomly picks a direction and starts to move along the edge of the triangle. What is the probability that none of the ants collide?
So let’s think this through. The ants can only avoid a collision if they all decide to move in the same direction (either clockwise or anti-clockwise). If the ants do not pick the same direction, there will definitely be a collision. Each ant has the option to either move clockwise or anti-clockwise. There is a one in two chance that an ant decides to pick a particular direction. Using simple probability calculations, we can determine the probability of no collision.
P(No collision) = P(All ants go in a clockwise direction) + P( All ants go in an anti-clockwise direction) = 0.5 * 0.5 * 0.5 + 0.5 * 0.5 * 0.5 = 0.25
You have been given the task of transporting 3,000 apples 1,000 miles from Appleland to Bananaville. Your truck can carry 1,000 apples at a time. Every time you travel a mile towards Bananaville you must pay a tax of 1 apple but you pay nothing when going in the other direction (towards Appleland). What is highest number of apples you can get to Bananaville?
Step one: First you want to make 3 trips of 1,000 apples 333 miles. You will be left with 2,001 apples and 667 miles to go.
Step two: Next you want to take 2 trips of 1,000 apples 500 miles. You will be left with 1,000 apples and 167 miles to go (you have to leave an apple behind).
Step three: Finally, you travel the last 167 miles with one load of 1,000 apples and are left with 833 apples in Bananaville.