1. Olympiad puzzle math problem in fifth grade of primary school 1
1. The speed of the ship in still water is15km per hour, and the speed of the current is 2km per hour. It took 13 hours for the ship to disembark from Port A to Port B. How many hours does it take to return from Port B to Port A? Analysis: Ship speed+water speed = downstream speed, then the downstream speed is 17km/h ... and the traveling time along the river is 13 hours, so the distance between Port A and Port B can be calculated. When returning home, it was sailing against the current. When the current speed is 13km/, the return time can be calculated by dividing the distance by the current speed.
Solution: (15+2) ×13 = 221(km)
221÷ (15-2) =17 (hours)
A: it takes 17 hours to return from port b to port a. ..
2. A ship travels between two ports, with a total length of 240 kilometers, sailing upstream 15 hours and sailing downstream 12 hours. What is the speed and water speed of a ship sailing in still water?
Analysis: divide the distance by the time of countercurrent travel to find out the speed of water flow; Divide the travel time along the river by the distance to find the speed along the river. Ship speed = (downstream speed+upstream speed) ÷2, current speed = downstream speed-ship speed.
Solution: Upstream velocity: 240 ÷ 15 = 16 (km/h).
Downstream speed: 240 ÷ 12 = 20 (km/h)
Ship speed: (16+20) ÷ 2 = 18 (km/h)
Water speed: 20- 18 = 2 (km/h)
A: The speed of a ship sailing in still water is18km/h, and the speed of water is 2km/h. ..
2. Mathematical Problems of Olympiad in Grade Five Primary School 2
1, granary A contains 43 tons of flour, and granary B contains 37 tons of flour. If the flour from granary B is put into granary A, then after granary A is full, the remaining flour from granary B accounts for 1/2 of granary B's capacity. If the flour from granary A is put into granary B, after granary B is full, the remaining flour from granary A accounts for 1/3 of granary A's capacity. How many tons of flour can each granary hold? Answer and analysis:
Because the sum of the capacity of the two granaries is the same, the total amount of flour of 43+37=80 tons has not changed.
So the price difference between granary B and granary A is 1- 1/2= 1/2 and 1- 1/3=2/3 respectively.
It shows that 1/2 of granary B and 2/3 of granary A have the same capacity.
Therefore, the capacity of warehouse B is 2/3+0/2 = 4/3 of that of warehouse A.
Therefore, the capacity of warehouse A is 80÷( 1+4/3÷2)=48 tons.
The capacity of warehouse B is 48×4/3=64 tons.
Party A and Party B ride bicycles from the same place on the ring road at the same time, and walk with their backs to each other. It is now known that A takes 70 minutes to walk around. If A and B meet 45 minutes after departure, then the time for B to walk around is _ _ _ _ minutes?
Answer and analysis:
A Walk for 45 minutes, and then walk 70-45=25 (minutes) to complete a circle. And A can walk for 45 minutes, and B can walk for 45 minutes to complete a lap. So a 25-minute walk is equivalent to 45 minutes for B and 70 minutes for A, so B needs 70÷25×45= 126 (minutes) ... that is, the time for B to walk once is 126 minutes.
3. The fifth grade elementary school mathematical problems in Olympiad III
1, there is a clock. Every time it rings, the sound lasts for 3 seconds. If the bell rings six times, it takes 43 seconds from the first bell to the end of the last continuous tone. Now ring 12, from the first sound to the end of the last continuous tone, a * * *, how long does it take? 2. Party A and Party B practice running. If Party A lets Party B run 10 meter first, Party A can catch up with Party B after running for 5 seconds. If B runs 2 seconds ahead of A, A can catch up with B in 4 seconds. Q: How many meters do two people run per second?
Both Party A and Party B ride bicycles from East Village to West Village at 8: 00 in the morning, and Party A is 6 kilometers faster than Party B every hour. After arriving at the West Village at noon 12, Party A immediately returned to the East Village and met Party B at the West Village15km. Q: How far apart are these two villages?
4. Party A, Party B and Party C walk 60m, 50m and 40m respectively. Party A starts from place B, while Party B and Party C start from place A at the same time. On the way, Party A met Party B and Party C on 15. Find the distance between a and b.
5. Party A and Party B leave from A and B respectively at the same time. If driving in the same direction, Party A will catch up with Party B by 26 points; If two people go in opposite directions, they can meet at 6 o'clock. Knowing that each branch of B is 50 meters, find the distance between A and B..
4. The fifth grade elementary school math problem 4
1. There are three steel pipes, which are 200 cm, 240 cm and 360 cm long. Now we are going to cut these three steel pipes into as long and equal sections as possible. How many segments can a * * * be cut into? 2. The two iron wires are 65m long and 9 1 m long respectively. Measure it with a wooden ruler, all of it has just been finished, and there is no extra. What is the maximum length of this wooden ruler?
3. Distribute 22 erasers and 33 pencils to the students who take part in cleaning the classroom. The result is 1 eraser, and two pencils are missing. How many students took part in the cleaning?
4. The number A is 5 larger than the number B, and the number B is 5 larger than the number C. The product of three numbers is 6384. Find these three numbers.
5. The number obtained by adding 6 or subtracting 6 from a prime number is still a prime number. How many such prime numbers can you find within 50? And write them down.
5. The fifth grade elementary school olympiad math problem five
1, some bread is shared by Party A, Party B and Party C, with Party A eating more than half of 1, Party B eating more than half of 1, Party C eating more than half of 1, and thus all the bread is eaten. How much bread is there? 2. There are 95 students in Class A and Class B, 8 students in Class A are transferred to Class B, and 35 students in Class B are transferred to Class C. At this time, the number of students in Class A is twice that of Class B. How many students are there in Class A and Class B?
Six cats caught six mice in six minutes. /kloc-how many cats does it take to catch 0/00 minutes 100 mice?
4. Once upon a time, A, B and C appraised an antique. A said it was worth at least 500 articles, B said it was less than 500 articles, and C said it was worth at least one article. Later, I learned that only one of the three people was right. How much is this antique worth?
5. It takes 1 minute to boil water, 1 minute to boil water, 1 minute to wash coffee cups and 2 minutes to make coffee in Zhang Gang. How many minutes is the most reasonable arrangement for guests to have coffee early?