1. Why is the cover of the sewer round? 2. How many cars are there in America? You let workers work for you for seven days, and the reward is a gold bar. This gold bar is divided into seven consecutive parts. At the end of each day, you must give them a gold bar. If you are only allowed to break the gold bars twice, will you pay the workers? 4. One train leaves Los Angeles for new york at the speed of 15km per hour, and another train leaves new york for Los Angeles at the speed of 20km per hour. If there is a bird, at the speed of 30 kilometers per hour, two trains are starting at present, and Biluo Mountain starts, meets another train and returns, flying back and forth between the two trains in turn until the two trains meet, how long has the bird been used to it? You have two jars, 50 red marbles and 50 blue marbles. Choose a jar at random and put a marble in the jar at random. How can we give red marbles the best chance to be selected? What is the exact probability of getting the red ball in your plan? 6. Imagine yourself in front of a mirror. Excuse me, why can the image in the mirror be upside down, but not upside down? 7. You have a can of pills for four people, and each pill has a certain weight. The contaminated pill is the uncontaminated weight+1. You only weigh it once. How do you know which jar is polluted? 8. If you have unlimited water, a 3-quart bucket and a 5-quart bucket, how can you accurately weigh 4 quarts of water? 9. You have a bucket of jelly, including yellow, green and red. Close your eyes, choose two of the same color and catch two of the same color. How many can you catch to make sure you have two jellies of the same color? 10. Insert the car key into the door and turn it in which direction to unlock the car? 1 1. If you could remove any of the 50 states, which one would you remove and why? Mathematical articles

1、 1000! How many digits are there? Why 2, f (n) =1n >; 8n & lt； 12F(n)= 2n & lt； 2F(n) = 3n = 6f (n) = 4n = other+-*/and sign(n) functions are combined to form the F(n) function sign (n) = 0n = 0sign (n) =-1n.

Only five minutes, give up after five minutes, because you will never be recruited by Microsoft. This is an intelligence test when Microsoft recruits! ! ! ! More than 5 minutes, eliminated! ! ! ! 1 It takes an hour to burn an uneven rope. How can it be used to judge half an hour? 2。 . . . . . . . . Please use only one stroke and four straight lines to connect all the points in Figure 9 above. 3 For a batch of lamps numbered 1~ 100, all the switches are turned on (connected): turn the switch in the opposite direction every multiple of 1; A multiple of 2 toggles the switch in the opposite direction again; A multiple of 3, toggle the switch again in the opposite direction. . . . . . Q: Finally, the number of lights that are off. Some Microsoft test questions

1, U2 choir will arrive at the concert venue in 17 minutes, and cross a bridge on the way. Four people start from the same end of the bridge. You have to help them reach the other end. It was dark and they only had one flashlight. At most two people cross the bridge at a time, and they must hold flashlights when crossing the bridge, so someone has to walk back and forth at both ends of the bridge with flashlights. You can't send out the flashlight if you throw it away. Four people walk at different speeds. If two people go together, the slower one shall prevail. Bono needs 1 min. It takes 2 minutes to cross the bridge. Adam needs 5 minutes to cross the bridge. Larry needs 10 minutes to cross the bridge. How can they cross the bridge in 17 minutes? (This is a question asked by Micrsoft when recruiting personnel. You must answer in five minutes before you can get the job. 2. There are 10 red balls, 10 white balls and two identical bags. How to place them to make it possible to take any ball from the bag? how much is it? 3. How many kinds of three-level and four-level binary trees are there? 4.1-100000 This series is arranged in a certain order, and one number is wrong. How to correct it? Write the best method. What about two numbers? Answer part: 1: Burn from both ends and burn for one hour. 2: A rice-shaped painting will do. 3: prime number off, the rest on. Answer: Microsoft recruitment intelligence test is underlined: first set the coordinates of the four corners of the square as (0,0), (0,3), (3,0), (3,3). 1000! How many digits are there? Why: 1000Lg( 1000! ) =sum(Lg(n))n= 1 If one curve is replaced by three broken lines,10 (0+1)/2+90 (1+2)/2+900 (2+3) can be obtained. f(n)= 1n & gt； 8n & lt； 12F(n)= 2n & lt； 2F(n) = 3n = 6f (n) = 4n = other+-*/and sign(n) functions are combined to form the F(n) function sign (n) = 0n = 0sign (n) =-1n.