IBM social recruitment pen questions

1. A long and straight pipe with uniform thickness, opening at both ends, containing four white balls and four black balls. The diameter of the ball and the diameter of the opening at both ends are equal to the diameter of the tube, currently, the white and black balls are arranged in wwwwbbbb format. You do not need to take out any balls and change them to bbwwwwbb.

2. A snail can climb from the bottom of the well to the wellhead. Every day, a snail can go to bed at night. A snail can climb 3 feet in one night, but it will fall 2 feet in the daytime, 10 feet in depth. How many days can a snail bait crawl out?

3. How many parts can be divided into by drawing 1999 straight lines on a plane?

4. A person who lives on a small island in the Pacific Ocean does not want to be disturbed by outsiders. One day, an explorer arrives on the island and is captured by the natives. the priests of the natives tell him, before you die, you can have a chance to leave a sentence. If this sentence is true, you will be burned to death. It is a false sentence. You will be split by five horses. How can poor explorer survive?

5. How to plant four trees to make the distance between any two trees equal.

After participating in the competition, 6.27 Small athletes are thirsty and impatient. They go to the store to buy drinks, and the beverage shop to make promotions. With three empty bottles, they can change to another one, how many drinks can they buy at least to ensure one person and one bottle?

7. there is a mountain with a temple on the mountain. There is only one way to go from the temple on the mountain to the foot of the mountain. Every Monday at, there is a clever little monk who goes down the mountain to save his fortune, at a.m. on Tuesday, I walked back to the temple on the mountain. The speed of the monk's mountain going up and down is arbitrary. In every round trip, he can always arrive at the same point on the mountain road at the same hour on Monday and Tuesday. For example, he once found that at on Monday and on Tuesday, he went to 3/4 on the foot of the mountain road and asked why?

8. There are two unevenly distributed fragrances, each of which is burned for an hour. How can you determine a period of 15 minutes?