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The total length of a bridge is 161 meters. It is planned to install 16 billboards on the railings on both sides of the bridge. The length of each billboard is 2 meters. The billboards at both ends are 12 meters from the bridge end. The distance between two adjacent billboards is equal. The distance between two adjacent billboards is calculated
Let the distance between two adjacent billboards be a
16*2+2*12+15a=161
a=7
There are 15 seats in a row of chairs. When Xiaoli comes, there are already some seats taken. Xiaoli finds that no matter which seat he is sitting in, he will be adjacent to the people who are already seated. Before Xiaoli comes, there are at least () people who have been seated
（1）8；（2）7；（3）6；（4）5
The answer is (4)
It is shown as follows:
Empty man, empty man, empty man, empty man, empty man, empty man, empty man, empty man
It takes 100 seconds for a motorcade to slowly cross a 210 long bridge at a speed of 5 meters per second. It is known that each vehicle is 5 meters long and the distance between the two vehicles is 10 meters. Then, how many vehicles are there in the motorcade?
The motorcade has to walk through the bridge: 100 * 5 = 500 (m)
In fact, the 500 meters include not only the length of the bridge, but also the length of the motorcade
Team leader: 500-210 = 290 (m)
If you add a 10 to the 290, it's just a car with a gap
290 + 10 = 300 (m)
Total vehicles: 300 / (10 + 5) = 20 (vehicles)
Sincerely: come on! If you don't understand, ask again and answer sincerely!
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