Urgent 5th grade math Olympiad problems with analysis, with translation .

Just ask my brother!

From the first encounter to the second encounter, they walked two round-trips, which took 4 hours, that is, a total of two hours to walk back and forth, and when they met for the first time, A walked 80 kilometers, that is, 2 hours to walk 80 kilometers, and the speed was 40 kilometers per hour. B starts from the first encounter and travels 80 kilometers to A, and then 60 kilometers from A, sharing 4 hours at a speed of 140 4 = 35 kilometers per hour.

I didn't see anyone doing it above just now, but the first floor is wrong, and the second floor is right. However, my analysis is easy to understand!

The first encounter, car A and car B traveled a total of 1 full length, car A traveled 1 80 kilometers for the second encounter, car A and car B traveled a total of 3 full lengths, car A traveled 3 80 kilometers, and car A traveled 2 with a total length of 60 kilometers, and the total length was (80 3 60) 2 150 (kilometers) When they met for the second time, car A traveled 80 3 240 (kilometers) and car A traveled 240 4 60 (kilometers) per hour

On the second encounter, car B traveled 150 3 240 210 (km) and car B traveled 210 4 km per hour).

1.From the first encounter to the second encounter.

B (towards A) walked a total of 80+60 140km and took 4 hours, so B's speed was 35km h.

2.From the first encounter to the second encounter, A and B walked a total of 2 whole journeys, which took 4 hours, so A and B walked a total of 2 hours.

3.The first encounter between the two cars took a total of 1 whole journey, so it can be seen that it took 2 hours, so the speed of car A (to B) was 80 2 40km hours, and the other way: the whole journey was 150km

Full Journey: (80 3+60) 2 150 (km) The first encounter took one full journey, and by the second encounter, two more full journeys were traveled for a total of four hours, so the speed of car A was 80 (4 2) 40 (km) per hour

Car B traveled 80+60 140 (km).

And because both cars traveled for 4 hours, the speed of car B was 140 4 35 (km/h).

Continue to draw the line segment diagram.

A and B met for the first time, and a total of 1 whole course.

A traveled 80 kilometers.

From the first encounter to the second encounter, A and B traveled 2 whole courses, of which B traveled 80 + 60 = 140 kilometers.

B speed per hour: 140 4 = 35 km/h.

A and B travel a total of 1 full time: 4 2 = 2 hours.

A per hour: 80 2 = 40 km.

1 Let the speed of the water x, then the speed of the ship 3x, then 16(3x+x)=192 x=3

It takes 192 (3x-x) = 192 to return to Port A, 6 = 32 hours2 Set the water velocity x and the speed of A y

Then 4(x+y)=120

6(y-x)=120 The solution yields x=5 y=25 and the velocity z of B

Then 8 (z+5) = 120 solution Z = 10, then B returns 120 (10-5) = 24 hours.

1.The speed of going down the river relative to the river bank is 4 v of water, and the speed of going up the river is 2 v of water, so it takes 16 2 to return to 32 hours.

V water is equal to 30 km per hour, v v water is equal to 20 km per hour, and v water is equal to 5 km per hour. v B v water is equal to 120 8 is equal to 15 kilometers per hour, v B is equal to 10 kilometers per hour, and when the reverse current, the speed of B relative to the river bank is 10 5 5 kilometers per hour, so B takes 120 5 24 hours against the current.

1: Let the water flow rate x, then 4x*16=192 This problem is solved.

2: Set the water flow velocity x, then the downstream velocity of boat A is 30, and the countercurrent velocity is 20, x=(30-20) 2=5 There is no difficulty in this problem.

This is from **.,It seems to have been done.,I'll check the homework book I've done.,But I have to send you which homework book this is.,I'm easy to find.。

1. A construction site needs tons of loess, and it has been transported 10 times with a truck with a deadweight ton, and the rest has been transported by a truck with a deadweight ton, how many times will it be transported?

2. The fertilizer plant plans to produce 540 tons of fertilizer in 36 days, how many tons does it produce in a day on average?

3. There are 190 tons of water in pool A and 78 tons of water in pool B. Feed the water from pool A into pool B at a rate of 8 tons per minute, and after a few minutes, the water volume of the two pools will be equal?

There is no correct answer. The area of the triangle is ( )cm. If the area of the parallelogram is 64cm, the area of the triangle is (32)cm.

1、（2）

Now the 5th grade question, we 6th graders all think Alexander!!

The right angle of an isosceles right triangle is 8 dm long, the area of this triangle is (32 dm, and the area of a parallelogram of equal height is (64 dm. Two identical trapezoids are put together into a parallelogram, the area of this parallelogram is 280cm, the height is 35cm, and the sum of the upper and lower bottoms of each trapezoid is (8

cm。Cut the largest triangle from a rectangular cardboard 40 decimeters long and 30 decimeters wide, and the area of this triangle is (600 cm.