Detailed steps to find a 6th grade math Olympiad problem

According to the title: B is faster than A, then B has gone more than A: 18*2=36 (km) So:

B travels more per hour than A: 36 3 = 12 (km) because: time is the same, so:

The distance ratio of A and B is equal to the speed ratio = 2:3, so the ratio of each copy is:

12 (3-2) = 12 (kmh) So: A's velocity is: 12*2=24 (kmh) B's velocity is:

12*3=36 (kmh).

The distance between the two cities: (24+36)*3=180 (km).

Solution: Speed of B: (18 km/h.)

Speed of A: (18 kmh.)

A: A's speed is 24 km/h, and B's speed is 36kmh.

Because car A and car B meet at a distance of 18 kilometers from the midpoint, the distance ratio is 2:3It can be seen that car B travels 18 kilometers more than car A at the midpoint, and car B travels 18*2=36 kilometers more than car A in the city. 36 kilometers is one portion, car A is two copies, and car B is three copies.

Therefore, the distance traveled by car A is 36*2=72 (km) and car B is 36*3=108 (km).

Then the speed of car A is 72 3 = 24 (km) Car B 108 3 = 36 (km) Answer: Car A is 24 km and car B is 36 km.

According to the 2:3 ratio of the distance traveled by car A and car B, the distance of car B is long, 18 kilometers more than half of the total distance, and the distance of car A is 18 kilometers less than half of the total distance, that is, car B travels 36 kilometers more than car A. It is also known that car A traveled two-fifths of the total distance, car B traveled three-fifths of the total distance, and car B traveled one-fifth more than car A, so the total distance is 36 1 5 = 180 (kilometers), and the speed of car A is.

180 2 5 3 = 24 (kmh), and the speed of car B is 180 3 5 3 = 36 (kmh).

2*18 3 (3-2)=12 (kmh) Car B is 12 km faster than Car A per hour.

3*A=2*B.

3*A=2*(A+12).

3*A = 2*A + 2*12

3 * A = 2 * A + 24

3 * A = 2 * A + 24

3-2)*A=24

1*A = 24

A = 24 B = 24 + 12

B = 36 Answer: A's speed is 24 km/h, and B's speed is 36 km/h.

The two cities are located at a distance of x kilometers. The midpoint is 2 = km from Castle Ko. The meeting point of the two vehicles is 2x 5 = kilometers away from Castle A.

So (km, x = 180 km.)

The distance traveled by car A in 3 hours is kilometers, and the speed is 72 3 = 24 kilometers per hour.

Similarly, car B has a speed of 36 km/h.

I don't know if I learned the equation in the sixth grade of primary school, if I have learned the first floor, the solution is very good, if I have not learned, I can draw line segments.

Because the distance ratio is 2:3, draw a line segment and divide it into five parts, A, two, B, and three meet at a distance of 18 kilometers from the midpoint, then it can be seen that the length of a section is 18*2=36

So the distance traveled by A is 36*2=72, the speed is 72 3=24, the distance traveled by B is 36*3=108, and the speed is 108 3=36

1. Salt: 50 5% = kg).

Water: kg) 2, (2 52% + 3 38%) 2 + 3) 100% = 3, solution: let the water added for the second time be x

3÷（100+x）=2%

x=50 The concentration after the third addition is 100 100%=2%.

5. If x kg of sugar water with a concentration of 22% is required, 1000-x kg of sugar water with a concentration of 27% is required.

Sugar water with a concentration of 22% 25% 1000 = 22% x + 27% (1000-x).

x = 400 sugar water with a concentration of 27% 1000-400 = 600 kg.

1.salt: 5-50 kg).

water: 50 kg).

2.（2×52％＋3×38％）÷2＋3）×100％＝3.Let the original brine be x kg and the concentration is y, then the added water is z kg.

(x z) 3 (x 2z) 2 i.e. x zxy (x z) 3 i.e. y 6

So x 6 (x 3z).

20％－20÷（20＋100）×100％≈5.Sugar water with a concentration of 22 is required: (1000 27 1000 25) 27 22 ) 400 (g).

Requires saline at a concentration of 27: 1000 400 600 (g).

33%5:50 5%=2,Go.

3÷（100+x）=2%

x=50 The concentration after the third addition is, let the water added for the second time be kilogram 100 100%=2%.

20%-20 120 100% 3, then 1000-x kg of sugar water with a concentration of 27%, (2 52% + 3 38% 2 + 3) 100% = kg).

Water, set the concentration of 22% sugar water x kilograms: 50-2, is to ask you to find 50 kilograms of salt and water in each kilogram.

Salt: 2 (150+50) 100%=1%.

Because every hour is 4 minutes slow, 8:30 to 12 o'clock is the hour, 4 minutes late, so at 12 o'clock this alarm time is 12 o'clock - 14 minutes = 11:46, the actual time of this alarm clock is 14 * 60 56 = 15 minutes.

So it will take another 15 minutes to point to 12 o'clock.

It takes 210 minutes from 8:30 to 12 noon standard time, 210 60 is the hour, multiplied by 4 minutes is 14 minutes.

The answer is 14 minutes.

At 12 o'clock in standard time, this clock is 14 minutes slower, that is, 11:46, then 4 minutes per hour is 4 60 is equivalent to 1 * 15 per minute slower, 14 minutes is 14 * 1 15 = 14 15, then the time required is 14 minutes slow plus the clock goes 14 minutes slow time, (14 + 14 15) minutes, I don't know if there is such a question so early in the current primary school, and I want to ask about the one in front, the clouds are light and the wind is light, (The actual time of 14 minutes of this alarm clock is 14 * 60 56 = 15 minutes, and 60 * 56 here is what it means) If you see it, you can tell me how it came.

In the first problem, if the subtracted number is x, then (49-x) (79-x)=2 7, and the equation is solved to obtain x=37

The second question assumes that there are x volleyballs, then there are 100-x footballs, and the total selling price is 15x+20*(100-x)*3 4=1500 yuan.

A batch of rice was stored in two grain depots, and the amount of rice stored in warehouse A was 2 3 that of warehouse B, and later 45 tons were transported to warehouse A and 36 tons to warehouse B, and the weight of rice in the two grain depots was equal. How many tons of rice was originally in Jiaku?

Warehouse A turned out to be less than warehouse B: 45 36 9 (tons).

Original: 9 (1 2 3) 27 (tons).

A warehouse original: 27 2 3 18 (tons).

Answer: The original 18 tons of rice in Jiaku.

The difference between the grain stored in warehouse A and warehouse B is 45-36 = 9 tons, the original warehouse B is 9 (1-2 3) = 27 tons, and the original warehouse A is 27 2 3 = 18 tons.

It's simple. I am also in the sixth grade, and I often do this kind of question: from the amount of rice stored in the first bank is 2 3 of the second store, it can be seen that there are 3 parts of the second store, and 2 copies of the first store, so if they are equal, you have to transport one copy to the first store, but now it is 45 tons to the first store, and 36 tons to the second store, then use 45 minus 36, which is equal to 9, indicating that one part is 9, and then just use 9 times 2 (don't multiply by 3, because what is sought is the original) can be.

Of course, I used the number of copies.

Equation: 45 36 9 (tons) 9 2 18 (tons).