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Mathematical parity feature
5 1 There is a three-person team and you can stand in X row.

A threesome can stand (X+8) rows, because there are eight rows less than a threesome, in other words, there are eight rows more than a threesome, so eight rows should be added.

The foursome can stand in (X-5) rows, because the foursome is five rows less than the threesome, so it needs to be reduced by five rows.

See that 4 is a multiple of 2, and the number of rows in a four-person team is definitely a multiple of a two-person team. Then the number of rows of a four-person team must be half that of a two-person team, and vice versa.

Multiply the number of four-person queues by 2 = the number of two-person queues: so 2(X-5)=X+8, and finally calculate X= 18.

Then a three-person team can stand in row X, then a three-person team can stand in row 18, so the total number of people is 18 times 3 equals 54 people.

Then how many rows a five-person pedestrian can stand is 54 people divided by 5, which is equal to 10, and exceeds 454 ÷ 5 =10 ```` 4.

That is to say, 10 has four people standing in the row, but four people can stand in one row (although it is not enough), so add a row10+1=1.

So a group of five people can stand in row 1 1, and the answer is C.

There are 70 people guaranteed. So 69 people didn't reach 70, and 50 people didn't reach 70. At this time, the 50-person part cannot be added, because the maximum number of people is 50. Only the top three can continue to look for a job. At this time, the person who found a job is

There are 69 people in software design, 69 in marketing, 69 in financial management and 50 in human resource management, totaling 257 people. At this time, one more person of any kind is 70 people who meet the meaning of the question, so 257+ 1 is 258 people.

Choose C.

53 * * * loss = 25000-10000 =15000 yuan.

A bear the loss = 15000× 2/3 = 10000 yuan.

B bear the loss =5000 yuan.

So: B should share = money paid-money lost =15000-5000 =10000 yuan.

Option a

Let each piano teacher take X and Latin teacher take Y. According to the meaning of the question, it is 5x+6y=76. First, according to the parity characteristics, we know that X must be an even number. In the problem, X is required to be a prime number, and 2 is the only even number among all prime numbers, so x=2. Substitution gives y= 1 1, so there are 4× 2 students left.

Option d

The speed of a boat equipped with power paddles is three times that of water. Now you just need to paddle downstream from A to B by hand, which takes 2/5 less time than when you come back. How many times the speed of a boat with power paddles in still water is that of manual paddles?

If the speed of manual paddling in still water is X, then the speed of water is x/2, and the time to paddle down the river by hand alone is A, and the speed of a boat in still water with full power paddle is Y times that of manual paddling; According to the condition of equal round-trip distance, we get:

(x+x/2)a =(yx-x/2)*( 1-2/5)a

3x/2=(y- 1/2)(3x/5)

1/2=y/5- 1/ 10

y=3

That is, the speed of a fully powered paddle in still water is three times that of a manual paddle.