Solve a math problem that is super difficult!! It s the title

1.Container A has 30 liters of 15% brine and container B has 20 liters of 18% brine, if the same amount of water is added to each of the two containers so that their concentration is equal, then how much water is added?

2.If A does a project alone, it will be completed at the specified time; If B does it alone, it will take 3 more days than the specified date to complete, and now after 2 days of cooperation between teams A and B, team B will do it alone, and it will be completed on the specified date.

3.A pool has two inlet pipes of A and B, and after opening two pipes of A and B at the same time for 4 hours, close the B pipe, and the A pipe used 6 hours to inject the pool. The water injection of tube A is the same for 2 hours and 30 minutes and tube B for 2 hours.

How many hours does it take to open the two pipes of A and B separately to fill the empty water pool?

4.Last winter, Manager Wang used 80,000 yuan to buy a batch of clothing, a 58 yuan per piece of sales, the result is not to seek, and then with 17,600 yuan enough to enter the quantity is twice the first time, the unit price is more expensive than the first time 4 yuan of the same clothing continues to sell, considering the change of seasons, and finally the remaining 150 pieces are sold at a 20% discount, and they are sold out soon. Q: How many costumes are in this batch?

Is the clothing store's business a profit or a loss? For how much.

There are no hardest questions, just boundless knowledge!

Three 5s and a 1 are calculated by four to get 24?

Trapezoidal surface (top bottom + 10 + bottom + 10) * height 2 (top bottom next to the bottom + bottom bottom) * high 2 + 10 * high 24 + 10 * high.

Because it can't be determined in the chain.

Therefore, it is not certain how much the area has increased.

So choose. d.Can't answer.

The trapezoidal area of the original eggplant envy = (upper bottom + lower bottom) * height 2 = 24 current trapezoidal area = (upper positive rent bottom + 10 + lower bottom + 10) * height 2 increased area = (upper bottom + 10 + lower bottom + 10) * high 2 - (upper bottom lifting nano + lower bottom) * high 2

Do you know for sure? I choose D

Let C be x, then A is 3*(x 2-22) and B is 4*(x 2-22).

then x+3*(x 2-22)+4*(x 2-22)=260

Solution x=92

Let the value of 1 3 of A score and 1 4 of B score and half of C score minus 22 points as x3x+4x+2(x+22)=260x=24

Is this a difficult question? Hehe.

1) Certificate: G is the midpoint of BE, F is the midpoint of BC.

BCE, GF EC

In the same way, in BCE, FH be

The opposite side is parallel. The quadrilateral EGFH is a parallelogram.

2)∵ef⊥bc

EFB and EFC are both right-angled triangles.

ef = bc, and f is the midpoint of bc bf=fc ef=bf=fc

EFB and EFC are both isosceles right-angled triangles.

and g is the midpoint of be, and h is the midpoint of ec.

fg⊥be fh⊥eh

eh⊥be ge⊥eh

The adjacent sides are all perpendicular to each other, the angles are all 90°, and the sides are of equal length, and the quadrilateral shape is square.

First, the median line theorem gf = EH fh = ge ok

Connect the gh median line gh =bf because ef= bc ef=gh gh is not parallel = 1 2bc ef bc that gh ef.

The diagonal lines are perpendicular and equal to the square.

The indefinite integral result is not the only derivative, and the verification should be able to improve the computational power of the differential calculation.

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