1. Light two incense sticks at the same time, one at one end and the other at both ends. When the two incense sticks are burned out, light one end and burn the other end of the incense stick. From now on The time from start to finish is 15 minutes;
2.12\10\6
12+16=28
2+8=10
2.12\10\6
12+16=28
2+8=10
p>
1+0=1
3 13=1+1+11=1+2+10=1+3+9=1+4+8=1+5+7= 1+6+6
=2+2+9=2+3+8=2+4+7=2+5+6
=3+3+7= 3+4+6=3+5+5
=4+4+5
***There are the above 14 possibilities, and the products are 11, 20, 27, and 32 respectively. , 35, 36, 36, 48, 56, 60, 42, 72, 75, 80
The subordinates already know the age of the manager, but they still cannot determine the ages of the manager’s three daughters. According to the age of the manager, they are still The ages of the three daughters cannot be determined. The only possibility is that the manager’s age is 36 years old, =1+6+6 =2+2+9
Only one daughter’s hair is black, so the ages of the three daughters are 2, 2, 9 years old;
3. It should be calculated like this: three out of 27, of which 2 went to the worker and 25 to the boss. For 30 yuan, the boss got 25, the worker got 2, and the three customers got back 3;
4. Tear off the label of each pair of socks, one for each person
5 .The time when the two cars meet × the flight speed of the bird is 30 kilometers/hour, which is 6/7 of the whole journey.
6. Put a red ball in one jar, 49 red balls and 50 blue balls in another jar. The probability is close to 75%. This is the maximum probability that can be achieved. In fact, as long as there are <50 red balls in one jar, no basketballs, and the remaining balls in the other jar, the probability of getting out the red balls is greater than 50%.
Take 1 pill from jar 7.1, Take 2 pills from the No. 2 can, 3 pills from the No. 3 can, and 4 pills from the No. 4 can. Weigh the 10 pills. How much heavier than the normal weight is the can size?
8.2-4
p>9. The first time it was all off
The second time the light that was a multiple of 2 was turned on
The third time it was both an even number and a multiple of 3 ( That is, multiples of 6) lights are turned off
So the lights that are turned off
1.3.5.7.9 and other odd numbers are turned off
6.12.18.24.30.36 .42.48.54.60.66.72.78.84.90.96 is also relevant
10. The axis of mirror symmetry is the central axis of a person
11. There are three people wearing black hats. Suppose there are N people wearing black. When N=1, black people can be sure that they are black when they see that others are white. So there should be a sound when the lights are turned off for the first time. It can be concluded that N>1. For each person wearing black, he can see N-1 black hats, and thus assumes that he is white. But after waiting for N-1 times and no one hits him, every black person will know that he is also black. So when you turn off the lights for the Nth time, N people will hit you.