The volume of the film is equal before and after deployment.
It is a cylinder before expansion and a cuboid after expansion. The height of a cuboid is 0.04 cm.
Before expansion: 3.14 *10 *10 * 80-3.14 * 4 * 80 = 3.14 * 84 * 80 cubic centimeters.
So the expanded area is: 3. 14*84*80/0.04=527520 square centimeters.
2. Write 1, 2, 3, ... in order of 2008, and the remainder is 1 234567891112 ... 20072008 divided by 9 is.
Add up all the remainder of 1-2008 and divide it by 9, so because 2007 is a multiple of 9, only 2008 remains, and the remainder after division by 9 is 1.
3. Write 1, 2, 3, 4, 5, 6, 7, 8, 9 as a line in any order, where three adjacent numbers can form seven three-digit numbers according to their order in the arrangement. For each arrangement of 1 ~ 9, the corresponding seven three digits are added. Then the minimum value of the sum of these three digits is (1998).
The minimum value should be 123. Each person adds up to 18.
4. Fill in "+"or "-"in the following □ to make the operation result 0.
1 1□ 10□9□8□7□6□5□4□3□2□ 1
1 1- 10-9+8+7-6-5+4+3-2- 1=0
Let the product of two digits be a four-digit formula "Beibei× Jingjing = Welcome to Beijing" (originally, this underline should be on the word, but I can't type it out, sorry! The characters in ~ ~) represent the numbers 1, 2, 3, 4, 5, and the same characters represent the same numbers. Then, Bei× Jing = (12); Four-digit "Welcome to Beijing" =( 1452).
North is 3, Beijing is 4, North is 1, Huan is 5, it should be 2.
6. In the following formula, the same Chinese characters represent the same numbers, and different Chinese characters represent different numbers.
Beibei+Jingjing+Huanhuan+Yingying+Nini = Fuwa.
Then the smallest three digits represented by "Fuwa" are (165).
Bei: 1, Jing 2, Huan 3, Ying 4, Ni 5.
7. Multiple commodities are delivered to 65,438+000 stores, and each store has at least one. No four stores have the same quantity of goods. Then there are at least (133) items.
Three families have the same number of pieces,
So three 1 block, three 2 blocks and three 3 blocks. ....
100/3=33 remainder 1
So there are three 1~33, plus 1 34.
Therefore, the minimum number of goods =33*3+34= 133.
8. There are some balls in the bag. They are just different in color, and everything else is exactly the same, including 10 red, 8 yellow and 2 blue. Then take at least (9) balls at a time to ensure that the colors of the four balls are the same.
9. It is known that the five-digit "8***8" can be divisible by 2008, so the quotient of division is (4 1).
Team A, Team B and Team C need 10 days to complete a project. As we all know, A's work efficiency is three times that of B, and B's work efficiency is twice that of C. During the construction period, Team A rested for four days, Team B rested for nine days, Team A and Team B could not rest at the same time, and Team C did not rest. Then the number of days the three teams work together is (2 days).
Solution: According to the meaning of the problem, it can be listed as
[ 10*( 1+2+3)-(4*2+4)-(9*3+9)]/( 1+2+3)
=(60- 12-36)/6
=2 days
The number of days for three teams to work together is 2 days.
1 1, A and B, two engineering teams, originally planned to undertake projects A and B respectively. As we all know, the work efficiency of Construction Team A is twice that of Construction Team B ... If A and B undertake projects B and A respectively, at this time, the time for completing these two projects will be increased by 50% than originally planned, and the ratio of the quantities of projects A and B will be (1; 2)。
12, Zhou Xiao drove to the conference center. Twenty minutes after the departure, it was delayed for 20 minutes because of traffic jam. In order to arrive at the convention center on time, Zhou Xiao accelerated the speed by 25% and finally arrived on time. Zhou Xiao took * * * minutes from departure to arrival at the convention center.
13, Xiao Zhang was sitting on the train with his back to the direction of the train, and a high-speed bus passed opposite Xiao Zhang. It took 9 seconds for the high-speed bus to pass by Xiao Zhang from front to back. If the speed of the high-speed bus is 120km/h and the speed of Xiao Zhang's train is 60km/h, then the length of the high-speed bus is (450m) m (120+60)/3.6 = 50m/s.
50 * 9 = 450m
14, it takes Xiao Qiang 3 hours to get from a to b by bike. If he walks 2 kilometers first and the walking speed is one-third of the cycling speed, then he will arrive in 20 minutes, so the distance between A and B is (18) kilometers.
18km. Multiply 2 km by 3 (because the walking speed is 65438+ 0/3 of the riding speed) to get 6 km, 2 km is 20 minutes, so 6 km is 60 minutes. It can be seen that riding is 1 hour and walking for 6 kilometers for 3 hours is 18 kilometers.
Write these today, there is no time, and I will help you tomorrow.